{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-115700", "assignerOrgId": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db", "state": "PUBLISHED", "assignerShortName": "EEF", "dateReserved": "2026-10-25T17:30:02.231Z", "datePublished": "2026-10-26T13:49:02.744Z", "dateUpdated": "2026-10-26T13:49:02.744Z" }, "containers": { "cna": { "affected": [ { "collectionURL": "https://repo.hex.pm", "cpes": [ "cpe:2.3:a:benoitc:hackney:*:*:*:*:*:*:*:*" ], "defaultStatus": "unaffected", "modules": [ "hackney_url" ], "packageName": "hackney", "packageURL": "pkg:hex/hackney", "product": "hackney", "programFiles": [ "src/hackney_url.erl" ], "programRoutines": [ { "name": "hackney_url:normalize/2" } ], "repo": "https://github.com/benoitc/hackney", "vendor": "benoitc", "versions": [ { "lessThan": "4.9.0", "status": "affected", "version": "4.0.1", "versionType": "semver" } ] }, { "collectionURL": "https://github.com", "cpes": [ "cpe:2.3:a:benoitc:hackney:*:*:*:*:*:*:*:*" ], "defaultStatus": "unaffected", "modules": [ "hackney_url" ], "packageName": "benoitc/hackney", "packageURL": "pkg:github/benoitc/hackney", "product": "hackney", "programFiles": [ "src/hackney_url.erl" ], "programRoutines": [ { "name": "hackney_url:normalize/2" } ], "repo": "https://github.com/benoitc/hackney", "vendor": "benoitc", "versions": [ { "lessThan": "f19561a0b422376348c91537e51377ab7325f4ee", "status": "affected", "version": "452620a92ec1da2e6b4862a049a2a4f04b42068f", "versionType": "git" } ] } ], "configurations": [ { "lang": "en", "supportingMedia": [ { "base64": false, "type": "text/html", "value": "

The application passes URLs that an untrusted party can influence to hackney and relies on its own host allowlist, built on uri_string:parse/1 or inet:parse_address/1, to keep requests away from internal addresses.

" }, { "base64": false, "type": "text/markdown", "value": "The application passes URLs that an untrusted party can influence to hackney and relies on its own host allowlist, built on `uri_string:parse/1` or `inet:parse_address/1`, to keep requests away from internal addresses." } ], "value": "The application passes URLs that an untrusted party can influence to hackney and relies on its own host allowlist, built on uri_string:parse/1 or inet:parse_address/1, to keep requests away from internal addresses." } ], "cpeApplicability": [ { "nodes": [ { "cpeMatch": [ { "criteria": "cpe:2.3:a:benoitc:hackney:*:*:*:*:*:*:*:*", "versionEndExcluding": "4.9.0", "versionStartIncluding": "4.0.1", "vulnerable": true } ], "negate": false, "operator": "OR" } ], "operator": "AND" } ], "credits": [ { "lang": "en", "type": "finder", "value": "Eurico Nicacio" }, { "lang": "en", "type": "reporter", "value": "Eurico Nicacio" }, { "lang": "en", "type": "remediation developer", "value": "Benoit Chesneau" }, { "lang": "en", "type": "coordinator", "value": "Jonatan Männchen / EEF" } ], "dateAssigned": "2026-10-26T10:12:09.000Z", "datePublic": "2026-10-25T00:00:00.000Z", "descriptions": [ { "lang": "en", "supportingMedia": [ { "base64": false, "type": "text/html", "value": "

Interpretation Conflict vulnerability in hackney_url in benoitc hackney allows Server Side Request Forgery via a percent-encoded bracketed IPv6 literal or an IP literal with a trailing dot. A host such as %5B%3A%3Affff%3A127%2E0%2E0%2E1%5D (decoding to [::ffff:127.0.0.1]) or 127.0.0.1. is not an IP address to a caller's allowlist built on uri_string:parse/1 and inet:parse_address/1, while hackney connects to the address it denotes. The same applies to a Location target when redirects are followed.

\n

The IP-literal gate that hackney_url:normalize/2 applies to a percent-decoded host, added to close the percent-encoded IP bypass of CVE-2026-47076, passes the decoded value to inet_parse:address/1 as is. The connect path in hackney_happy:parse_address/1 drops a surrounding bracket pair, and the resolver ignores a trailing dot, so both forms pass the gate and still reach the literal address. Domain names with a trailing dot and unencoded IPv6 literals are not affected.

\n

This issue affects hackney: from 4.0.1 before 4.9.0.

" }, { "base64": false, "type": "text/markdown", "value": "Interpretation Conflict vulnerability in `hackney_url` in benoitc hackney allows Server Side Request Forgery via a percent-encoded bracketed IPv6 literal or an IP literal with a trailing dot. A host such as `%5B%3A%3Affff%3A127%2E0%2E0%2E1%5D` (decoding to `[::ffff:127.0.0.1]`) or `127.0.0.1.` is not an IP address to a caller's allowlist built on `uri_string:parse/1` and `inet:parse_address/1`, while hackney connects to the address it denotes. The same applies to a `Location` target when redirects are followed.\n\nThe IP-literal gate that `hackney_url:normalize/2` applies to a percent-decoded host, added to close the percent-encoded IP bypass of CVE-2026-47076, passes the decoded value to `inet_parse:address/1` as is. The connect path in `hackney_happy:parse_address/1` drops a surrounding bracket pair, and the resolver ignores a trailing dot, so both forms pass the gate and still reach the literal address. Domain names with a trailing dot and unencoded IPv6 literals are not affected.\n\nThis issue affects hackney: from 4.0.1 before 4.9.0." } ], "value": "Interpretation Conflict vulnerability in hackney_url in benoitc hackney allows Server Side Request Forgery via a percent-encoded bracketed IPv6 literal or an IP literal with a trailing dot. A host such as %5B%3A%3Affff%3A127%2E0%2E0%2E1%5D (decoding to [::ffff:127.0.0.1]) or 127.0.0.1. is not an IP address to a caller's allowlist built on uri_string:parse/1 and inet:parse_address/1, while hackney connects to the address it denotes. The same applies to a Location target when redirects are followed.\n\nThe IP-literal gate that hackney_url:normalize/2 applies to a percent-decoded host, added to close the percent-encoded IP bypass of CVE-2026-47076, passes the decoded value to inet_parse:address/1 as is. The connect path in hackney_happy:parse_address/1 drops a surrounding bracket pair, and the resolver ignores a trailing dot, so both forms pass the gate and still reach the literal address. Domain names with a trailing dot and unencoded IPv6 literals are not affected.\n\nThis issue affects hackney: from 4.0.1 before 4.9.0." } ], "impacts": [ { "capecId": "CAPEC-664", "descriptions": [ { "lang": "en", "supportingMedia": [ { "base64": false, "type": "text/html", "value": "

An application that checks user-supplied URLs against an IP allowlist before handing them to hackney can be made to request loopback, link-local metadata and private-network addresses that the allowlist rejects when they are written plainly.

" }, { "base64": false, "type": "text/markdown", "value": "An application that checks user-supplied URLs against an IP allowlist before handing them to hackney can be made to request loopback, link-local metadata and private-network addresses that the allowlist rejects when they are written plainly." } ], "value": "An application that checks user-supplied URLs against an IP allowlist before handing them to hackney can be made to request loopback, link-local metadata and private-network addresses that the allowlist rejects when they are written plainly." } ] } ], "metrics": [ { "cvssV4_0": { "Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "Safety": "NOT_DEFINED", "attackComplexity": "LOW", "attackRequirements": "PRESENT", "attackVector": "LOCAL", "baseScore": 6.9, "baseSeverity": "MEDIUM", "privilegesRequired": "NONE", "providerUrgency": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "subConfidentialityImpact": "HIGH", "subIntegrityImpact": "NONE", "userInteraction": "NONE", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N", "version": "4.0", "vulnAvailabilityImpact": "NONE", "vulnConfidentialityImpact": "HIGH", "vulnIntegrityImpact": "NONE", "vulnerabilityResponseEffort": "NOT_DEFINED" }, "format": "CVSS", "scenarios": [ { "lang": "en", "value": "GENERAL" } ] } ], "problemTypes": [ { "descriptions": [ { "cweId": "CWE-436", "description": "CWE-436 Interpretation Conflict", "lang": "en", "type": "CWE" } ] }, { "descriptions": [ { "cweId": "CWE-918", "description": "CWE-918 Server-Side Request Forgery (SSRF)", "lang": "en", "type": "CWE" } ] } ], "providerMetadata": { "orgId": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db", "shortName": "EEF", "dateUpdated": "2026-10-26T13:49:02.744Z" }, "references": [ { "name": "hackney 4.9.0 release notes", "tags": [ "vendor-advisory", "related" ], "url": "https://github.com/benoitc/hackney/releases/tag/4.9.0" }, { "name": "EEF CNA record for CVE-2026-115700", "tags": [ "related" ], "url": "https://cna.erlef.org/cves/CVE-2026-115700.html" }, { "name": "OSV record EEF-CVE-2026-115700", "tags": [ "related" ], "url": "https://osv.dev/vulnerability/EEF-CVE-2026-115700" }, { "name": "Refuse bracketed and trailing-dot IP literals in normalize/2 (benoitc/hackney#987)", "tags": [ "related" ], "url": "https://github.com/benoitc/hackney/pull/987" }, { "name": "Introducing commit 452620a in benoitc/hackney", "tags": [ "related" ], "url": "https://github.com/benoitc/hackney/commit/452620a92ec1da2e6b4862a049a2a4f04b42068f" }, { "name": "Fix commit f19561a in benoitc/hackney", "tags": [ "patch" ], "url": "https://github.com/benoitc/hackney/commit/f19561a0b422376348c91537e51377ab7325f4ee" } ], "source": { "discovery": "EXTERNAL" }, "title": "SSRF allowlist bypass via percent-encoded bracketed IPv6 or trailing-dot IP literal in hackney", "workarounds": [ { "lang": "en", "supportingMedia": [ { "base64": false, "type": "text/html", "value": "

Run the allowlist on the host that hackney_url:normalize/1 returns for the parsed URL, and strip a surrounding bracket pair and a trailing dot from it before the IP check, so the check sees the same address the connect path uses.

" }, { "base64": false, "type": "text/markdown", "value": "Run the allowlist on the host that `hackney_url:normalize/1` returns for the parsed URL, and strip a surrounding bracket pair and a trailing dot from it before the IP check, so the check sees the same address the connect path uses." } ], "value": "Run the allowlist on the host that hackney_url:normalize/1 returns for the parsed URL, and strip a surrounding bracket pair and a trailing dot from it before the IP check, so the check sees the same address the connect path uses." } ], "x_technicalAnalysis": [ { "lang": "en", "supportingMedia": [ { "base64": false, "type": "text/html", "value": "

1. The gate. hackney_url:normalize/2 in src/hackney_url.erl percent-decodes a host that is not already an IP literal and raises invalid_url_host when inet_parse:address/1 accepts the decoded value. This closed the plain percent-encoded IP case.

\n

2. What the connect path accepts. hackney_happy:parse_address/1 removes a surrounding [...] pair before calling inet:parse_address/1, and the resolver treats a trailing dot as the root label. Neither form is accepted by inet_parse:address/1, so [::ffff:127.0.0.1] and 127.0.0.1. pass the gate.

\n

3. Result. A percent-encoded bracketed IPv6 literal such as %5B%3A%3Affff%3A127%2E0%2E0%2E1%5D, or an IPv4 literal with a trailing dot, is not an IP address to a caller's check based on uri_string:parse/1 and inet:parse_address/1, but hackney connects to the address it denotes. The same applies to a Location target when redirects are followed. The fix strips one bracket pair and one trailing dot in ip_candidate/1 before the gate.

" }, { "base64": false, "type": "text/markdown", "value": "**1. The gate.** `hackney_url:normalize/2` in `src/hackney_url.erl` percent-decodes a host that is not already an IP literal and raises `invalid_url_host` when `inet_parse:address/1` accepts the decoded value. This closed the plain percent-encoded IP case.\n\n**2. What the connect path accepts.** `hackney_happy:parse_address/1` removes a surrounding `[...]` pair before calling `inet:parse_address/1`, and the resolver treats a trailing dot as the root label. Neither form is accepted by `inet_parse:address/1`, so `[::ffff:127.0.0.1]` and `127.0.0.1.` pass the gate.\n\n**3. Result.** A percent-encoded bracketed IPv6 literal such as `%5B%3A%3Affff%3A127%2E0%2E0%2E1%5D`, or an IPv4 literal with a trailing dot, is not an IP address to a caller's check based on `uri_string:parse/1` and `inet:parse_address/1`, but hackney connects to the address it denotes. The same applies to a `Location` target when redirects are followed. The fix strips one bracket pair and one trailing dot in `ip_candidate/1` before the gate." } ], "value": "1. The gate. hackney_url:normalize/2 in src/hackney_url.erl percent-decodes a host that is not already an IP literal and raises invalid_url_host when inet_parse:address/1 accepts the decoded value. This closed the plain percent-encoded IP case.\n\n2. What the connect path accepts. hackney_happy:parse_address/1 removes a surrounding [...] pair before calling inet:parse_address/1, and the resolver treats a trailing dot as the root label. Neither form is accepted by inet_parse:address/1, so [::ffff:127.0.0.1] and 127.0.0.1. pass the gate.\n\n3. Result. A percent-encoded bracketed IPv6 literal such as %5B%3A%3Affff%3A127%2E0%2E0%2E1%5D, or an IPv4 literal with a trailing dot, is not an IP address to a caller's check based on uri_string:parse/1 and inet:parse_address/1, but hackney connects to the address it denotes. The same applies to a Location target when redirects are followed. The fix strips one bracket pair and one trailing dot in ip_candidate/1 before the gate." } ] } } }