{"id":"EUVD-2026-16890","revision":null,"records":[{"revision":"a83fa0e30abe4ef2b2f082e4e146cabf","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-33994","aliases":[],"title":"Locutus Prototype Pollution due to incomplete fix for CVE-2026-25521","description":"Locutus brings stdlibs of other programming languages to JavaScript for educational purposes. Starting in version 2.0.39 and prior to version 3.0.25, a prototype pollution vulnerability exists in the `parse_str` function of the npm package locutus. An attacker can pollute `Object.prototype` by overriding `RegExp.prototype.test` and then passing a crafted query string to `parse_str`, bypassing the prototype pollution guard. This vulnerability stems from an incomplete fix for CVE-2026-25521. The CVE-2026-25521 patch replaced the `String.prototype.includes()`-based guard with a `RegExp.prototype.test()`-based guard. However, `RegExp.prototype.test` is itself a writable prototype method that can be overridden, making the new guard bypassable in the same way as the original — trading one hijackable built-in for another. Version 3.0.25 contains an updated fix.","state":0,"publishedAt":"2026-03-27T22:15:47.131+00:00","modifiedAt":"2026-04-01T13:45:55.451+00:00","affected":[{"ecosystem":"Vendor product","name":"locutus","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"vendor\": \"locutusjs\",\n                    \"product\": \"locutus\",\n                    \"versions\": [\n                        {\n                            \"version\": \">= 2.0.39, < 3.0.25\",\n                            \"status\": \"affected\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 4.0","vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N","score":6.3,"severity":"MEDIUM"}],"references":["https://github.com/locutusjs/locutus/security/advisories/GHSA-vc8f-x9pp-wf5p","https://github.com/locutusjs/locutus/pull/597","https://github.com/locutusjs/locutus/commit/345a6211e1e6f939f96a7090bfeff642c9fcf9e4","https://github.com/locutusjs/locutus/releases/tag/v3.0.25"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-33994","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-33994","identifiers":["CVE-2026-33994"]},"retained":false,"historicalAffected":[]},{"revision":"0b9c597cb45d4fe5bfa7e8c23edeea04","observedAt":"2026-11-01T06:05:13.899+00:00","statement":{"source":"euvd","id":"EUVD-2026-16890","aliases":["CVE-2026-33994","GHSA-vc8f-x9pp-wf5p"],"title":"Locutus brings stdlibs of other programming languages to JavaScript for educational purposes. Starting in version 2.0.39 and prior to version 3.0.25, a prototype pollution vulnerability exists in the `parse_str` function of the npm package …","description":"Locutus brings stdlibs of other programming languages to JavaScript for educational purposes. Starting in version 2.0.39 and prior to version 3.0.25, a prototype pollution vulnerability exists in the `parse_str` function of the npm package locutus. An attacker can pollute `Object.prototype` by overriding `RegExp.prototype.test` and then passing a crafted query string to `parse_str`, bypassing the prototype pollution guard. This vulnerability stems from an incomplete fix for CVE-2026-25521. The CVE-2026-25521 patch replaced the `String.prototype.includes()`-based guard with a `RegExp.prototype.test()`-based guard. However, `RegExp.prototype.test` is itself a writable prototype method that can be overridden, making the new guard bypassable in the same way as the original — trading one hijackable built-in for another. Version 3.0.25 contains an updated fix.","state":0,"publishedAt":null,"modifiedAt":null,"affected":[],"metrics":[{"system":"EUVD CVSS 4.0","vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N","score":6.3,"severity":null}],"references":["https://github.com/locutusjs/locutus/security/advisories/GHSA-vc8f-x9pp-wf5p","https://github.com/locutusjs/locutus/pull/597","https://github.com/locutusjs/locutus/commit/345a6211e1e6f939f96a7090bfeff642c9fcf9e4","https://github.com/locutusjs/locutus/releases/tag/v3.0.25"],"sourceUrl":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-16890","license":"ENISA EUVD · source terms and attribution apply","enrichment":{"sourceStatus":null,"weaknesses":[],"productCriteria":[],"sourceDates":{"datePublished":"Mar 27, 2026, 10:15:47 PM","dateUpdated":"Apr 1, 2026, 1:45:55 PM"},"relatedAdvisories":[],"note":"EUVD source date text has no stated timezone and is retained without inventing a UTC instant. Related bulletin membership is not an alias, common cause or applicability claim. A missing vector with a zero score is treated as unrated. Complete vendor/product and underlying source evidence remains in the original JSON."},"key":"euvd:EUVD-2026-16890","identifiers":["EUVD-2026-16890","CVE-2026-33994","GHSA-vc8f-x9pp-wf5p"]},"retained":false,"historicalAffected":[]},{"revision":"124ba604c2fc4649bbe09599e865fddb","observedAt":"2026-10-27T09:03:00.507+00:00","statement":{"source":"nvd","id":"CVE-2026-33994","aliases":[],"title":"Locutus brings stdlibs of other programming languages to JavaScript for educational purposes. Starting in version 2.0.39 and prior to version 3.0.25, a prototype pollution vulnerability exists in the `parse_str` function of the npm package …","description":"Locutus brings stdlibs of other programming languages to JavaScript for educational purposes. Starting in version 2.0.39 and prior to version 3.0.25, a prototype pollution vulnerability exists in the `parse_str` function of the npm package locutus. An attacker can pollute `Object.prototype` by overriding `RegExp.prototype.test` and then passing a crafted query string to `parse_str`, bypassing the prototype pollution guard. This vulnerability stems from an incomplete fix for CVE-2026-25521. The CVE-2026-25521 patch replaced the `String.prototype.includes()`-based guard with a `RegExp.prototype.test()`-based guard. However, `RegExp.prototype.test` is itself a writable prototype method that can be overridden, making the new guard bypassable in the same way as the original — trading one hijackable built-in for another. Version 3.0.25 contains an updated fix.","state":0,"publishedAt":"2026-03-27T23:17:14.413+00:00","modifiedAt":"2026-10-26T22:10:00.163+00:00","affected":[],"metrics":[{"system":"CVSS 4.0 · security-advisories@github.com · Secondary","vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","score":6.3,"severity":"MEDIUM"},{"system":"CVSS 3.1 · nvd@nist.gov · Primary","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","score":9.8,"severity":"CRITICAL"},{"system":"CVSS 3.1 · 134c704f-9b21-4f2e-91b3-4a467353bcc0 · Secondary","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","score":9.8,"severity":"CRITICAL"}],"references":["https://github.com/locutusjs/locutus/commit/345a6211e1e6f939f96a7090bfeff642c9fcf9e4","https://github.com/locutusjs/locutus/pull/597","https://github.com/locutusjs/locutus/releases/tag/v3.0.25","https://github.com/locutusjs/locutus/security/advisories/GHSA-vc8f-x9pp-wf5p"],"sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-33994","license":"NIST NVD usage terms; underlying source attribution retained","enrichment":{"sourceStatus":"Modified","weaknesses":["CWE-1321"],"productCriteria":["cpe:2.3:a:locutus:locutus:*:*:*:*:*:node.js:*:*"],"sourceDates":{"published":"2026-03-27T23:17:14.413","lastModified":"2026-10-26T22:10:00.163"},"relatedAdvisories":[],"note":"NVD analysis and CPE criteria are source context, not proof that a package or your environment is affected. Complete affected data, logical configurations and SSVC are retained in the original JSON."},"key":"nvd:CVE-2026-33994","identifiers":["CVE-2026-33994"]},"retained":false,"historicalAffected":[]},{"revision":"f310c08aea04459cac138ada6b82277b","observedAt":"2026-10-24T13:17:17.793+00:00","statement":{"source":"osv","id":"GHSA-vc8f-x9pp-wf5p","aliases":["CVE-2026-33994"],"title":"Locutus Prototype Pollution due to incomplete fix for CVE-2026-25521","description":"## Summary\n\nA prototype pollution vulnerability exists in the `parse_str` function of the npm package locutus. An attacker can pollute `Object.prototype` by overriding `RegExp.prototype.test` and then passing a crafted query string to `parse_str`, bypassing the prototype pollution guard.\n\nThis vulnerability stems from an incomplete fix for [CVE-2026-25521](https://github.com/locutusjs/locutus/security/advisories/GHSA-rxrv-835q-v5mh). The CVE-2026-25521 patch replaced the `String.prototype.includes()`-based guard with a `RegExp.prototype.test()`-based guard. However, `RegExp.prototype.test` is itself a writable prototype method that can be overridden, making the new guard bypassable in the same way as the original — trading one hijackable built-in for another.\n\n## Package\n\nlocutus (npm)\n\n## Affected versions\n\n>= 2.0.39, <= 3.0.24\n\nTested and confirmed vulnerable on **2.0.39** and **3.0.24** (latest). Version 2.0.38 (pre-fix) uses a different guard (`String.prototype.includes`) and is not affected by this specific bypass.\n\n---\n\n## Description\n\n### Details\n\nThe vulnerability resides in `parse_str.js` where the `RegExp.prototype.test()` function is used to check whether user-provided input contains forbidden keys:\n\n```javascript\nif (/__proto__|constructor|prototype/.test(key)) {\n  break\n}\n```\n\nThe previous guard (fixed in CVE-2026-25521) used `String.prototype.includes()`:\n\n```javascript\nif (key.includes('__proto__')) {\n  break\n}\n```\n\nThe CVE-2026-25521 fix correctly identified that `String.prototype.includes` can be hijacked. However, the replacement guard using `RegExp.prototype.test()` suffers from the same class of weakness — `RegExp.prototype.test` is a writable method on the prototype chain and can be overridden to always return `false`, completely disabling the guard.\n\nThe robust fix is to use direct string comparison operators (`===`) in native control flow (`for`/`if`) instead of prototype methods like `RegExp.prototype.test()`, since `===` is a language-level operator that cannot be overridden.\n\n### PoC\n\n#### Steps to reproduce\n\n1. Install locutus using `npm install locutus`\n2. Run the following code snippet:\n\n```javascript\nconst parse_str = require('locutus/php/strings/parse_str');\n\n// Hijack RegExp.prototype.test (simulates a prior prototype pollution gadget)\nconst original = RegExp.prototype.test;\nRegExp.prototype.test = function () { return false; };\n\n// Payload\nconst result = {};\nparse_str('__proto__[polluted]=yes', result);\n\n// Check\nRegExp.prototype.test = original;\nconsole.log(({}).polluted); // 'yes' — prototype is polluted\n```\n\n#### Expected behavior\n\nPrototype pollution should be prevented and `({}).polluted` should print `undefined`.\n\n```\nundefined\n```\n\n#### Actual behavior\n\n`Object.prototype` is polluted. This is printed on the console:\n\n```\nyes\n```\n\n### Impact\n\nThis is a prototype pollution vulnerability with the same impact as CVE-2026-25521. The attack requires a chaining scenario — an attacker needs a separate prototype pollution gadget (e.g., from another npm package in the same application) to override `RegExp.prototype.test` before exploiting `parse_str`. This is realistic in Node.js applications that use multiple npm packages, where one package's vulnerability can disable another package's defenses.\n\nAny application that processes attacker-controlled input using `locutus/php/strings/parse_str` may be affected. It could potentially lead to:\n\n1. Authentication bypass\n2. Denial of service\n3. Remote code execution (if polluted property is passed to sinks like `eval` or `child_process`)\n\n### Resources\n\n- Original advisory: https://github.com/locutusjs/locutus/security/advisories/GHSA-rxrv-835q-v5mh\n- Fix commit (incomplete): https://github.com/locutusjs/locutus/commit/042af9ca7fde2ff599120783e720a17f335bb01c\n- Vulnerable file: https://github.com/locutusjs/locutus/blob/main/src/php/strings/parse_str.js#L77\n\n## Maintainer response\n\nThank you for the follow-up report. This issue was reproduced locally against `locutus@3.0.24`, confirming that the earlier `parse_str` guard was incomplete: if `RegExp.prototype.test` was already compromised, the guard could be bypassed and `parse_str('__proto__[polluted]=yes', result)` could still pollute `Object.prototype`.\n\nThis is now fixed on `main` and released in `locutus@3.0.25`.\n\n## Fix Shipped In\n\n- **PR:** [locutusjs/locutus#597](https://github.com/locutusjs/locutus/pull/597)\n- **Merge commit on `main`:** `345a6211e1e6f939f96a7090bfeff642c9fcf9e4`\n- **Release:** [v3.0.25](https://github.com/locutusjs/locutus/releases/tag/v3.0.25)\n\n## What the Fix Does\n\nThe new fix no longer relies on a regex-prototype guard for safety. Instead, `src/php/strings/parse_str.ts` now rejects dangerous key paths during parsed-segment assignment, so the sink itself is hardened even if `RegExp.prototype.test` has been tampered with beforehand.\n\n## Tested Repro Before the Fix\n\n- Override `RegExp.prototype.test` to always return `false`\n- Call `parse_str('__proto__[polluted]=yes', result)`\n- Observe `({}).polluted === 'yes'`\n\n## Tested State After the Fix in `3.0.25`\n\n- Dangerous key paths are skipped during assignment\n- The same chained repro no longer pollutes `Object.prototype`\n- The regression is covered by `test/custom/parse_str-prototype-pollution.vitest.ts`\n\n---\n\nThe locutus team is treating this as a real package vulnerability with patched version `3.0.25`. The vulnerable range should end at `< 3.0.25`.","state":0,"publishedAt":"2026-03-27T17:58:48+00:00","modifiedAt":"2026-03-30T20:34:57.635752+00:00","affected":[{"ecosystem":"npm","name":"locutus","ranges":[{"type":"SEMVER","events":[{"kind":"introduced","version":"2.0.39"},{"kind":"fixed","version":"3.0.25"}]}],"versions":[],"rawVersionEvidence":null}],"metrics":[{"system":"CVSS_V4","vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N","score":null,"severity":null},{"system":"Publisher rating","vector":null,"score":null,"severity":"MODERATE"}],"references":["https://github.com/locutusjs/locutus/security/advisories/GHSA-rxrv-835q-v5mh","https://github.com/locutusjs/locutus/security/advisories/GHSA-vc8f-x9pp-wf5p","https://nvd.nist.gov/vuln/detail/CVE-2026-33994","https://github.com/locutusjs/locutus/pull/597","https://github.com/locutusjs/locutus/commit/345a6211e1e6f939f96a7090bfeff642c9fcf9e4","https://github.com/locutusjs/locutus","https://github.com/locutusjs/locutus/releases/tag/v3.0.25"],"sourceUrl":"https://github.com/advisories/GHSA-vc8f-x9pp-wf5p","license":"GitHub Advisory Database · CC-BY-4.0","key":"osv:GHSA-vc8f-x9pp-wf5p","identifiers":["GHSA-vc8f-x9pp-wf5p","CVE-2026-33994"]},"retained":false,"historicalAffected":[]}],"coverage":[{"source":"cisa-kev:global","scope":"Complete CISA KEV catalog; all vendors. Missing entries do not establish absence of exploitation.","generation":"2026-11-01T13:57:21.0120005+00:00","complete":true,"records":1766,"lastAttemptAt":"2026-11-01T13:57:21.0120005+00:00","lastSuccessAt":"2026-11-01T13:57:21.1632398+00:00","error":null,"lastVerifiedAt":"2026-11-01T13:57:21.1632407+00:00","snapshotPublishedAt":null,"importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"cve-program","scope":"Official CVE Program baseline and cumulative hourly delta; all vendors, published and rejected records","generation":"cve-aece262bb10a694367a43c24d730aa8e8dc171723eaec4c15cdd32f04bda103f-50400654721c20d1e62d5e20161fa1011500efbfa4660bff21fbf42ab394284d","complete":true,"records":417651,"lastAttemptAt":"2026-11-01T13:57:20.4803086+00:00","lastSuccessAt":"2026-11-01T13:57:20.4526709+00:00","error":null,"lastVerifiedAt":"2026-11-01T13:57:20.4803086+00:00","snapshotPublishedAt":"2026-11-01T13:22:02+00:00","importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"euvd","scope":"Rolling EUVD lookups of CVE aliases in current public OSV archives; 500 identifiers per refresh, rechecked after 48 hours. Not a global EUVD catalog. Successful not-found lookups count as checked; they do not imply withdrawal or safety. No reader inventory is sent.","generation":"enrichment-16dea3261a6142e0a956a04888eec4c6","complete":false,"records":13568,"lastAttemptAt":"2026-11-01T14:09:22.4460439+00:00","lastSuccessAt":"2026-11-01T14:09:22.442+00:00","error":null,"lastVerifiedAt":"2026-11-01T14:09:22.442+00:00","snapshotPublishedAt":null,"importing":false,"stagedRecords":0,"checkedIdentifiers":13443,"expectedIdentifiers":13637,"failedIdentifiers":0},{"source":"first-epss:nuget","scope":"FIRST EPSS for explicit CVE aliases in the collected public NuGet archive. Not a global EPSS backfill.","generation":"2026-11-01T13:57:21.0120005+00:00","complete":true,"records":1095,"lastAttemptAt":"2026-11-01T13:57:21.0120005+00:00","lastSuccessAt":"2026-11-01T13:57:21.1641254+00:00","error":null,"lastVerifiedAt":"2026-11-01T13:57:21.1641257+00:00","snapshotPublishedAt":null,"importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"nvd","scope":"Rolling NVD lookups of CVE aliases in current public OSV archives; 500 identifiers per refresh, rechecked after 48 hours. Not a global NVD catalog. Successful not-found lookups count as checked; they do not imply withdrawal or safety. No reader inventory is sent.","generation":"enrichment-40f3d0cdd04e4088bac6e8bb2fe516b0","complete":true,"records":13580,"lastAttemptAt":"2026-11-01T13:57:34.3841835+00:00","lastSuccessAt":"2026-11-01T13:57:34.38+00:00","error":null,"lastVerifiedAt":"2026-11-01T13:57:34.38+00:00","snapshotPublishedAt":null,"importing":false,"stagedRecords":0,"checkedIdentifiers":13637,"expectedIdentifiers":13637,"failedIdentifiers":0},{"source":"osv:Go","scope":"Complete OSV Go ecosystem archive, including withdrawn and malicious-package source records; statement counts are not unique CVE counts","generation":"go-21dcd6662970dfea02e4ea60ee637115e8d92664947484d2b9276b3f6568a84f","complete":true,"records":9815,"lastAttemptAt":"2026-11-01T13:57:20.8674133+00:00","lastSuccessAt":"2026-10-30T23:47:34.1817587+00:00","error":null,"lastVerifiedAt":"2026-11-01T13:57:20.8674133+00:00","snapshotPublishedAt":"2026-10-30T23:33:17+00:00","importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"osv:NuGet","scope":"Complete OSV NuGet ecosystem archive, including GitHub Advisory Database records; NuGet version matching only","generation":"nuget-2de9ccc5290f060c7aa63f89c25dd76f655a64ba1aba7c05c97fa3bee4f09899","complete":true,"records":1967,"lastAttemptAt":"2026-11-01T13:57:20.6544139+00:00","lastSuccessAt":"2026-10-28T20:55:34.2982937+00:00","error":null,"lastVerifiedAt":"2026-11-01T13:57:20.6544139+00:00","snapshotPublishedAt":"2026-10-28T20:03:08+00:00","importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"osv:crates.io","scope":"Complete OSV crates.io ecosystem archive, including withdrawn and malicious-package source records; statement counts are not unique CVE counts","generation":"crates.io-f95f76cd406ae5bae3de632ad37fd2d5160b44f5e6b51748ac6f8f0c0c88e72b","complete":true,"records":3028,"lastAttemptAt":"2026-11-01T13:57:20.9796516+00:00","lastSuccessAt":"2026-10-30T23:47:38.4914494+00:00","error":null,"lastVerifiedAt":"2026-11-01T13:57:20.9796516+00:00","snapshotPublishedAt":"2026-10-30T23:18:12+00:00","importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"osv:npm","scope":"Complete OSV npm ecosystem archive, including withdrawn and malicious-package source records; statement counts are not unique CVE counts","generation":"npm-55acacd40a7aab88cf530cfddf98233a5d800cfc6bb1883653ecf5bee50f4426","complete":true,"records":230996,"lastAttemptAt":"2026-11-01T13:57:20.7638808+00:00","lastSuccessAt":"2026-11-01T09:06:49.6961926+00:00","error":null,"lastVerifiedAt":"2026-11-01T13:57:20.7638808+00:00","snapshotPublishedAt":"2026-11-01T08:33:39+00:00","importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null}]}