CVE-2026-91767
Full vulnerability record from the local CVENow database.
Description
php_openssl_matches_wildcard_name() in ext/openssl/xp_ssl.c underflows the length argument passed to memchr() when a TLS server certificate presents a wildcard name whose literal characters are together longer than the hostname being verified. A malicious server presenting such a certificate makes the PHP client read up to SIZE_MAX bytes past the end of a heap allocation. The path is reachable from any default client stream, because verify_peer_name is enabled by default.
Severity
MEDIUM
CVSS score
6.5
(v3.1)
Vulnerability status
Analyzed
Source identifier
Published
2026-09-25 21:17:24.793000
Last modified
2026-10-27 13:14:13.607000
View original CVE JSON
{
"id": "CVE-2026-91767",
"sourceIdentifier": "[email protected]",
"published": "2026-09-25T21:17:24.793",
"lastModified": "2026-10-27T13:14:13.607",
"vulnStatus": "Analyzed",
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "php_openssl_matches_wildcard_name() in ext/openssl/xp_ssl.c underflows the length argument passed to memchr() when a TLS server certificate presents a wildcard name whose literal characters are together longer than the hostname being verified. A malicious server presenting such a certificate makes the PHP client read up to SIZE_MAX bytes past the end of a heap allocation. The path is reachable from any default client stream, because verify_peer_name is enabled by default."
}
],
"affected": [
{
"source": "[email protected]",
"affectedData": [
{
"vendor": "PHP Group",
"product": "PHP",
"defaultStatus": "unaffected",
"packageName": "ext-openssl",
"versions": [
{
"version": "8.2.*",
"lessThan": "8.2.34",
"versionType": "semver",
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},
{
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"versionType": "semver",
"status": "affected"
},
{
"version": "8.4.*",
"lessThan": "8.4.26",
"versionType": "semver",
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},
{
"version": "8.5.*",
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"versionType": "semver",
"status": "affected"
}
]
}
]
}
],
"metrics": {
"cvssMetricV31": [
{
"source": "[email protected]",
"type": "Secondary",
"cvssData": {
"version": "3.1",
"vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N",
"baseScore": 6.5,
"baseSeverity": "MEDIUM",
"attackVector": "ADJACENT_NETWORK",
"attackComplexity": "LOW",
"privilegesRequired": "NONE",
"userInteraction": "NONE",
"scope": "UNCHANGED",
"confidentialityImpact": "HIGH",
"integrityImpact": "NONE",
"availabilityImpact": "NONE"
},
"exploitabilityScore": 2.8,
"impactScore": 3.6
},
{
"source": "[email protected]",
"type": "Primary",
"cvssData": {
"version": "3.1",
"vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
"baseScore": 6.5,
"baseSeverity": "MEDIUM",
"attackVector": "ADJACENT_NETWORK",
"attackComplexity": "LOW",
"privilegesRequired": "NONE",
"userInteraction": "NONE",
"scope": "UNCHANGED",
"confidentialityImpact": "NONE",
"integrityImpact": "NONE",
"availabilityImpact": "HIGH"
},
"exploitabilityScore": 2.8,
"impactScore": 3.6
}
],
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"timestamp": "2026-09-28T12:56:38.307648Z",
"id": "CVE-2026-91767",
"options": [
{
"exploitation": "none"
},
{
"automatable": "no"
},
{
"technicalImpact": "partial"
}
],
"role": "CISA Coordinator",
"version": "2.0.3"
}
}
]
},
"weaknesses": [
{
"source": "[email protected]",
"type": "Secondary",
"description": [
{
"lang": "en",
"value": "CWE-122"
}
]
}
],
"configurations": [
{
"nodes": [
{
"operator": "OR",
"negate": false,
"cpeMatch": [
{
"vulnerable": true,
"criteria": "cpe:2.3:a:php:php:*:*:*:*:*:*:*:*",
"versionStartIncluding": "8.2.0",
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"matchCriteriaId": "AAFB3643-4D71-46ED-8184-DDE5FE41CD02"
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"references": [
{
"url": "https://github.com/php/php-src/security/advisories/GHSA-xr7j-rvgx-xq5p",
"source": "[email protected]",
"tags": [
"Vendor Advisory"
]
}
]
}