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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",
              "versionEndExcluding": "8.2.34",
              "matchCriteriaId": "AAFB3643-4D71-46ED-8184-DDE5FE41CD02"
            },
            {
              "vulnerable": true,
              "criteria": "cpe:2.3:a:php:php:*:*:*:*:*:*:*:*",
              "versionStartIncluding": "8.3.0",
              "versionEndExcluding": "8.3.35",
              "matchCriteriaId": "FF664EE8-D417-45A4-84DF-158F5073FDE8"
            },
            {
              "vulnerable": true,
              "criteria": "cpe:2.3:a:php:php:*:*:*:*:*:*:*:*",
              "versionStartIncluding": "8.4.0",
              "versionEndExcluding": "8.4.26",
              "matchCriteriaId": "52D4BECA-EF0D-4180-837C-AEFA7A12D243"
            },
            {
              "vulnerable": true,
              "criteria": "cpe:2.3:a:php:php:*:*:*:*:*:*:*:*",
              "versionStartIncluding": "8.5.0",
              "versionEndExcluding": "8.5.11",
              "matchCriteriaId": "308803C0-9FC8-40D2-8920-B83BCC48014F"
            }
          ]
        }
      ]
    }
  ],
  "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",
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "tags": [
        "Vendor Advisory",
        "Exploit"
      ]
    }
  ]
}