{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-115693", "assignerOrgId": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db", "state": "PUBLISHED", "assignerShortName": "EEF", "dateReserved": "2026-10-25T10:45:02.327Z", "datePublished": "2026-10-26T13:49:29.374Z", "dateUpdated": "2026-10-26T13:49:29.374Z"}, "containers": {"cna": {"affected": [{"collectionURL": "https://repo.hex.pm", "cpes": ["cpe:2.3:a:benoitc:hackney:*:*:*:*:*:*:*:*"], "defaultStatus": "unaffected", "modules": ["hackney_ssl"], "packageName": "hackney", "packageURL": "pkg:hex/hackney", "product": "hackney", "programFiles": ["src/hackney_ssl.erl"], "programRoutines": [{"name": "hackney_ssl:ssl_opts/2"}, {"name": "hackney_ssl:merge_ssl_opts/3"}, {"name": "hackney_ssl:partial_chain/1"}], "repo": "https://github.com/benoitc/hackney", "vendor": "benoitc", "versions": [{"lessThan": "4.9.0", "status": "affected", "version": "1.24.0", "versionType": "semver"}]}, {"collectionURL": "https://github.com", "cpes": ["cpe:2.3:a:benoitc:hackney:*:*:*:*:*:*:*:*"], "defaultStatus": "unaffected", "modules": ["hackney_ssl"], "packageName": "benoitc/hackney", "packageURL": "pkg:github/benoitc/hackney", "product": "hackney", "programFiles": ["src/hackney_ssl.erl"], "programRoutines": [{"name": "hackney_ssl:ssl_opts/2"}, {"name": "hackney_ssl:merge_ssl_opts/3"}, {"name": "hackney_ssl:partial_chain/1"}], "repo": "https://github.com/benoitc/hackney", "vendor": "benoitc", "versions": [{"lessThan": "915eb5737e9c489d8fc22eec8cdae30e9b027be4", "status": "affected", "version": "d8a9afcf5c3849904274e2eba1df56c63d1a1a0c", "versionType": "git"}]}], "configurations": [{"lang": "en", "supportingMedia": [{"base64": false, "type": "text/html", "value": "<p>The caller passes <code>cacerts</code> or <code>cacertfile</code> in <code>ssl_options</code> to restrict trust to a private CA, without a <code>partial_chain</code> of its own. Connections that use hackney's default certifi trust store are not affected.</p>"}, {"base64": false, "type": "text/markdown", "value": "The caller passes `cacerts` or `cacertfile` in `ssl_options` to restrict trust to a private CA, without a `partial_chain` of its own. Connections that use hackney's default certifi trust store are not affected."}], "value": "The caller passes cacerts or cacertfile in ssl_options to restrict trust to a private CA, without a partial_chain of its own. Connections that use hackney's default certifi trust store are not affected."}], "cpeApplicability": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:a:benoitc:hackney:*:*:*:*:*:*:*:*", "versionEndExcluding": "4.9.0", "versionStartIncluding": "1.24.0", "vulnerable": true}], "negate": false, "operator": "OR"}], "operator": "AND"}], "credits": [{"lang": "en", "type": "finder", "value": "Martin Karrer"}, {"lang": "en", "type": "remediation developer", "value": "Martin Karrer"}, {"lang": "en", "type": "coordinator", "value": "Jonatan M\u00e4nnchen / EEF"}], "dateAssigned": "2026-10-26T09:57:53.000Z", "datePublic": "2026-10-25T00:00:00.000Z", "descriptions": [{"lang": "en", "supportingMedia": [{"base64": false, "type": "text/html", "value": "<p>Improper Certificate Validation vulnerability in <code>hackney_ssl</code> in benoitc hackney allows an on-path attacker to impersonate a server pinned to a private certificate authority via a certificate chain that ends in a publicly trusted root. hackney adds <code>{partial_chain, fun hackney_ssl:partial_chain/1}</code> to every <code>verify_peer</code> configuration. The callback returns any certificate in the peer chain whose public key matches a root in the bundled certifi store as the trust anchor, and OTP honours that callback over the configured <code>cacerts</code>. <code>hackney_ssl:merge_ssl_opts/3</code> kept the callback when the caller replaced the trust store with <code>cacerts</code> or <code>cacertfile</code> in <code>ssl_options</code>, so a connection pinned to a private CA still accepted any chain that carried a publicly trusted root.</p>\n<p>The hostname check still applies, so the attacker needs a publicly trusted certificate for the pinned hostname.</p>\n<p>This issue affects hackney: from 1.24.0 before 4.9.0.</p>"}, {"base64": false, "type": "text/markdown", "value": "Improper Certificate Validation vulnerability in `hackney_ssl` in benoitc hackney allows an on-path attacker to impersonate a server pinned to a private certificate authority via a certificate chain that ends in a publicly trusted root. hackney adds `{partial_chain, fun hackney_ssl:partial_chain/1}` to every `verify_peer` configuration. The callback returns any certificate in the peer chain whose public key matches a root in the bundled certifi store as the trust anchor, and OTP honours that callback over the configured `cacerts`. `hackney_ssl:merge_ssl_opts/3` kept the callback when the caller replaced the trust store with `cacerts` or `cacertfile` in `ssl_options`, so a connection pinned to a private CA still accepted any chain that carried a publicly trusted root.\n\nThe hostname check still applies, so the attacker needs a publicly trusted certificate for the pinned hostname.\n\nThis issue affects hackney: from 1.24.0 before 4.9.0."}], "value": "Improper Certificate Validation vulnerability in hackney_ssl in benoitc hackney allows an on-path attacker to impersonate a server pinned to a private certificate authority via a certificate chain that ends in a publicly trusted root. hackney adds {partial_chain, fun hackney_ssl:partial_chain/1} to every verify_peer configuration. The callback returns any certificate in the peer chain whose public key matches a root in the bundled certifi store as the trust anchor, and OTP honours that callback over the configured cacerts. hackney_ssl:merge_ssl_opts/3 kept the callback when the caller replaced the trust store with cacerts or cacertfile in ssl_options, so a connection pinned to a private CA still accepted any chain that carried a publicly trusted root.\n\nThe hostname check still applies, so the attacker needs a publicly trusted certificate for the pinned hostname.\n\nThis issue affects hackney: from 1.24.0 before 4.9.0."}], "impacts": [{"capecId": "CAPEC-94", "descriptions": [{"lang": "en", "supportingMedia": [{"base64": false, "type": "text/html", "value": "<p>An attacker positioned between the client and a server pinned to a private CA, holding a publicly trusted certificate for the pinned hostname, can impersonate the server and read or modify the traffic the client sends and receives.</p>"}, {"base64": false, "type": "text/markdown", "value": "An attacker positioned between the client and a server pinned to a private CA, holding a publicly trusted certificate for the pinned hostname, can impersonate the server and read or modify the traffic the client sends and receives."}], "value": "An attacker positioned between the client and a server pinned to a private CA, holding a publicly trusted certificate for the pinned hostname, can impersonate the server and read or modify the traffic the client sends and receives."}]}], "metrics": [{"cvssV4_0": {"Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "Safety": "NOT_DEFINED", "attackComplexity": "HIGH", "attackRequirements": "PRESENT", "attackVector": "NETWORK", "baseScore": 9.1, "baseSeverity": "CRITICAL", "privilegesRequired": "NONE", "providerUrgency": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "userInteraction": "NONE", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N", "version": "4.0", "vulnAvailabilityImpact": "NONE", "vulnConfidentialityImpact": "HIGH", "vulnIntegrityImpact": "HIGH", "vulnerabilityResponseEffort": "NOT_DEFINED"}, "format": "CVSS", "scenarios": [{"lang": "en", "value": "GENERAL"}]}], "problemTypes": [{"descriptions": [{"cweId": "CWE-295", "description": "CWE-295 Improper Certificate Validation", "lang": "en", "type": "CWE"}]}], "providerMetadata": {"orgId": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db", "shortName": "EEF", "dateUpdated": "2026-10-26T13:49:29.374Z"}, "references": [{"name": "Drop the certifi partial_chain when the caller pins cacerts or cacertfile (benoitc/hackney#978)", "tags": ["related"], "url": "https://github.com/benoitc/hackney/pull/978"}, {"name": "EEF CNA record for CVE-2026-115693", "tags": ["related"], "url": "https://cna.erlef.org/cves/CVE-2026-115693.html"}, {"name": "OSV record EEF-CVE-2026-115693", "tags": ["related"], "url": "https://osv.dev/vulnerability/EEF-CVE-2026-115693"}, {"name": "hackney 4.9.0 release notes", "tags": ["vendor-advisory", "related"], "url": "https://github.com/benoitc/hackney/releases/tag/4.9.0"}, {"name": "Introducing commit d8a9afc in benoitc/hackney", "tags": ["related"], "url": "https://github.com/benoitc/hackney/commit/d8a9afcf5c3849904274e2eba1df56c63d1a1a0c"}, {"name": "Fix commit 915eb57 in benoitc/hackney", "tags": ["patch"], "url": "https://github.com/benoitc/hackney/commit/915eb5737e9c489d8fc22eec8cdae30e9b027be4"}], "source": {"discovery": "EXTERNAL"}, "title": "Custom cacerts or cacertfile do not restrict trust to the pinned CA in hackney", "workarounds": [{"lang": "en", "supportingMedia": [{"base64": false, "type": "text/html", "value": "<p>Pass your own <code>{partial_chain, Fun}</code> in <code>ssl_options</code> alongside <code>cacerts</code> or <code>cacertfile</code>. A caller-supplied <code>partial_chain</code> replaces hackney's in the merge, and a callback that returns <code>unknown_ca</code> makes OTP validate against the configured <code>cacerts</code> only.</p>"}, {"base64": false, "type": "text/markdown", "value": "Pass your own `{partial_chain, Fun}` in `ssl_options` alongside `cacerts` or `cacertfile`. A caller-supplied `partial_chain` replaces hackney's in the merge, and a callback that returns `unknown_ca` makes OTP validate against the configured `cacerts` only."}], "value": "Pass your own {partial_chain, Fun} in ssl_options alongside cacerts or cacertfile. A caller-supplied partial_chain replaces hackney's in the merge, and a callback that returns unknown_ca makes OTP validate against the configured cacerts only."}], "x_technicalAnalysis": [{"lang": "en", "supportingMedia": [{"base64": false, "type": "text/html", "value": "<p><strong>1. Default trust options.</strong> <code>hackney_ssl:check_hostname_opts/1</code> builds the <code>verify_peer</code> options for every TLS connection: the certifi <code>cacerts</code>, a hostname <code>verify_fun</code>, and <code>{partial_chain, fun hackney_ssl:partial_chain/1}</code>. The callback walks the peer chain and returns <code>{trusted_ca, Cert}</code> for the first certificate whose public key matches a root in the bundled certifi store, which lets OTP accept chains that end in a cross-signed root.</p>\n<p><strong>2. Merge keeps the callback.</strong> When the caller passes <code>ssl_options</code>, <code>hackney_ssl:merge_ssl_opts/3</code> merges them over the defaults with the caller's values winning per key. <code>cacerts</code> or <code>cacertfile</code> replace the trust store, and a <code>cacertfile</code> removes the default <code>cacerts</code>, but <code>partial_chain</code> has no counterpart in the caller's options and stays.</p>\n<p><strong>3. Validation.</strong> OTP consults <code>partial_chain</code> before the configured trust store. A peer chain that carries any publicly trusted root therefore gets that root as its trust anchor, and the pinned <code>cacerts</code> are never consulted. Only the hostname <code>verify_fun</code> still constrains the attacker.</p>"}, {"base64": false, "type": "text/markdown", "value": "**1. Default trust options.** `hackney_ssl:check_hostname_opts/1` builds the `verify_peer` options for every TLS connection: the certifi `cacerts`, a hostname `verify_fun`, and `{partial_chain, fun hackney_ssl:partial_chain/1}`. The callback walks the peer chain and returns `{trusted_ca, Cert}` for the first certificate whose public key matches a root in the bundled certifi store, which lets OTP accept chains that end in a cross-signed root.\n\n**2. Merge keeps the callback.** When the caller passes `ssl_options`, `hackney_ssl:merge_ssl_opts/3` merges them over the defaults with the caller's values winning per key. `cacerts` or `cacertfile` replace the trust store, and a `cacertfile` removes the default `cacerts`, but `partial_chain` has no counterpart in the caller's options and stays.\n\n**3. Validation.** OTP consults `partial_chain` before the configured trust store. A peer chain that carries any publicly trusted root therefore gets that root as its trust anchor, and the pinned `cacerts` are never consulted. Only the hostname `verify_fun` still constrains the attacker."}], "value": "1. Default trust options. hackney_ssl:check_hostname_opts/1 builds the verify_peer options for every TLS connection: the certifi cacerts, a hostname verify_fun, and {partial_chain, fun hackney_ssl:partial_chain/1}. The callback walks the peer chain and returns {trusted_ca, Cert} for the first certificate whose public key matches a root in the bundled certifi store, which lets OTP accept chains that end in a cross-signed root.\n\n2. Merge keeps the callback. When the caller passes ssl_options, hackney_ssl:merge_ssl_opts/3 merges them over the defaults with the caller's values winning per key. cacerts or cacertfile replace the trust store, and a cacertfile removes the default cacerts, but partial_chain has no counterpart in the caller's options and stays.\n\n3. Validation. OTP consults partial_chain before the configured trust store. A peer chain that carries any publicly trusted root therefore gets that root as its trust anchor, and the pinned cacerts are never consulted. Only the hostname verify_fun still constrains the attacker."}]}}}

{}

{"affected": [{"affectedData": [{"collectionURL": "https://repo.hex.pm", "cpes": ["cpe:2.3:a:benoitc:hackney:*:*:*:*:*:*:*:*"], "defaultStatus": "unaffected", "modules": ["hackney_ssl"], "packageName": "hackney", "packageURL": "pkg:hex/hackney", "product": "hackney", "programFiles": ["src/hackney_ssl.erl"], "programRoutines": [{"name": "hackney_ssl:ssl_opts/2"}, {"name": "hackney_ssl:merge_ssl_opts/3"}, {"name": "hackney_ssl:partial_chain/1"}], "repo": "https://github.com/benoitc/hackney", "vendor": "benoitc", "versions": [{"lessThan": "4.9.0", "status": "affected", "version": "1.24.0", "versionType": "semver"}]}, {"collectionURL": "https://github.com", "cpes": ["cpe:2.3:a:benoitc:hackney:*:*:*:*:*:*:*:*"], "defaultStatus": "unaffected", "modules": ["hackney_ssl"], "packageName": "benoitc/hackney", "packageURL": "pkg:github/benoitc/hackney", "product": "hackney", "programFiles": ["src/hackney_ssl.erl"], "programRoutines": [{"name": "hackney_ssl:ssl_opts/2"}, {"name": "hackney_ssl:merge_ssl_opts/3"}, {"name": "hackney_ssl:partial_chain/1"}], "repo": "https://github.com/benoitc/hackney", "vendor": "benoitc", "versions": [{"lessThan": "915eb5737e9c489d8fc22eec8cdae30e9b027be4", "status": "affected", "version": "d8a9afcf5c3849904274e2eba1df56c63d1a1a0c", "versionType": "git"}]}], "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "Improper Certificate Validation vulnerability in hackney_ssl in benoitc hackney allows an on-path attacker to impersonate a server pinned to a private certificate authority via a certificate chain that ends in a publicly trusted root. hackney adds {partial_chain, fun hackney_ssl:partial_chain/1} to every verify_peer configuration. The callback returns any certificate in the peer chain whose public key matches a root in the bundled certifi store as the trust anchor, and OTP honours that callback over the configured cacerts. hackney_ssl:merge_ssl_opts/3 kept the callback when the caller replaced the trust store with cacerts or cacertfile in ssl_options, so a connection pinned to a private CA still accepted any chain that carried a publicly trusted root.\n\nThe hostname check still applies, so the attacker needs a publicly trusted certificate for the pinned hostname.\n\nThis issue affects hackney: from 1.24.0 before 4.9.0."}], "id": "CVE-2026-115693", "lastModified": "2026-10-26T14:16:31.853", "metrics": {"cvssMetricV40": [{"cvssData": {"Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "Safety": "NOT_DEFINED", "attackComplexity": "HIGH", "attackRequirements": "PRESENT", "attackVector": "NETWORK", "availabilityRequirement": "NOT_DEFINED", "baseScore": 9.1, "baseSeverity": "CRITICAL", "confidentialityRequirement": "NOT_DEFINED", "exploitMaturity": "NOT_DEFINED", "integrityRequirement": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "privilegesRequired": "NONE", "providerUrgency": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "userInteraction": "NONE", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/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", "version": "4.0", "vulnAvailabilityImpact": "NONE", "vulnConfidentialityImpact": "HIGH", "vulnIntegrityImpact": "HIGH", "vulnerabilityResponseEffort": "NOT_DEFINED"}, "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db", "type": "Secondary"}]}, "published": "2026-10-26T14:16:31.853", "references": [{"source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db", "url": "https://cna.erlef.org/cves/CVE-2026-115693.html"}, {"source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db", "url": "https://github.com/benoitc/hackney/commit/915eb5737e9c489d8fc22eec8cdae30e9b027be4"}, {"source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db", "url": "https://github.com/benoitc/hackney/commit/d8a9afcf5c3849904274e2eba1df56c63d1a1a0c"}, {"source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db", "url": "https://github.com/benoitc/hackney/pull/978"}, {"source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db", "url": "https://github.com/benoitc/hackney/releases/tag/4.9.0"}, {"source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db", "url": "https://osv.dev/vulnerability/EEF-CVE-2026-115693"}], "sourceIdentifier": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db", "vulnStatus": "Received", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-295"}], "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db", "type": "Secondary"}]}

{}

{"created": "2026-10-26T15:30:15.149710+00:00", "updated": "2026-10-26T15:30:15.149724+00:00", "vendors": []}