CVE-2026-6103
Full vulnerability record from the local CVENow database.
Description
phar_tar_number() parses the octal size field of a TAR header into a uint32_t with no overflow check. The field is 11 octal digits wide and holds values up to 0x1FFFFFFFF, so a size above 0xFFFFFFFF silently wraps. The parser then skips the wrong number of data blocks and interprets attacker-controlled file content as the next TAR header, which lets a crafted archive inject entries that PharData reports and extracts as if they were genuine.
Severity
LOW
CVSS score
3.3
(v3.1)
Vulnerability status
Analyzed
Source identifier
Published
2026-09-25 21:17:23.790000
Last modified
2026-10-23 14:07:18.323000
View original CVE JSON
{
"id": "CVE-2026-6103",
"sourceIdentifier": "[email protected]",
"published": "2026-09-25T21:17:23.790",
"lastModified": "2026-10-23T14:07:18.323",
"vulnStatus": "Analyzed",
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "phar_tar_number() parses the octal size field of a TAR header into a uint32_t with no overflow check. The field is 11 octal digits wide and holds values up to 0x1FFFFFFFF, so a size above 0xFFFFFFFF silently wraps. The parser then skips the wrong number of data blocks and interprets attacker-controlled file content as the next TAR header, which lets a crafted archive inject entries that PharData reports and extracts as if they were genuine."
}
],
"affected": [
{
"source": "[email protected]",
"affectedData": [
{
"vendor": "PHP Group",
"product": "PHP",
"defaultStatus": "unaffected",
"versions": [
{
"version": "8.2.*",
"lessThan": "8.2.34",
"versionType": "semver",
"status": "affected"
},
{
"version": "8.3.*",
"lessThan": "8.3.35",
"versionType": "semver",
"status": "affected"
},
{
"version": "8.4.*",
"lessThan": "8.4.26",
"versionType": "semver",
"status": "affected"
},
{
"version": "8.5.*",
"lessThan": "8.5.11",
"versionType": "semver",
"status": "affected"
}
]
}
]
}
],
"metrics": {
"cvssMetricV31": [
{
"source": "[email protected]",
"type": "Secondary",
"cvssData": {
"version": "3.1",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N",
"baseScore": 4.3,
"baseSeverity": "MEDIUM",
"attackVector": "LOCAL",
"attackComplexity": "LOW",
"privilegesRequired": "NONE",
"userInteraction": "NONE",
"scope": "CHANGED",
"confidentialityImpact": "NONE",
"integrityImpact": "LOW",
"availabilityImpact": "NONE"
},
"exploitabilityScore": 2.5,
"impactScore": 1.4
},
{
"source": "[email protected]",
"type": "Primary",
"cvssData": {
"version": "3.1",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N",
"baseScore": 3.3,
"baseSeverity": "LOW",
"attackVector": "LOCAL",
"attackComplexity": "LOW",
"privilegesRequired": "LOW",
"userInteraction": "NONE",
"scope": "UNCHANGED",
"confidentialityImpact": "NONE",
"integrityImpact": "LOW",
"availabilityImpact": "NONE"
},
"exploitabilityScore": 1.8,
"impactScore": 1.4
}
],
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"timestamp": "2026-09-25T20:41:05.626504Z",
"id": "CVE-2026-6103",
"options": [
{
"exploitation": "poc"
},
{
"automatable": "no"
},
{
"technicalImpact": "partial"
}
],
"role": "CISA Coordinator",
"version": "2.0.3"
}
}
]
},
"weaknesses": [
{
"source": "[email protected]",
"type": "Secondary",
"description": [
{
"lang": "en",
"value": "CWE-190"
}
]
}
],
"configurations": [
{
"nodes": [
{
"operator": "OR",
"negate": false,
"cpeMatch": [
{
"vulnerable": true,
"criteria": "cpe:2.3:a:php:php:*:*:*:*:*:*:*:*",
"versionStartIncluding": "8.2.0",
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"references": [
{
"url": "https://github.com/php/php-src/security/advisories/GHSA-j3wh-g957-2m85",
"source": "[email protected]",
"tags": [
"Vendor Advisory",
"Exploit"
]
},
{
"url": "https://github.com/php/php-src/security/advisories/GHSA-j3wh-g957-2m85",
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}