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Vulnerability record · CVE-2026-6103 · published 25 September 2026

CVE-2026-6103: Php integer overflow vulnerability

Php · Php

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.

3.3 CVSS 3.1 Low EPSS 0.16% · top 94.8% CWE-190 · Integer overflow
3.3CVSS 3.1 base score
0.16%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
2References, 2 tagged exploit
23 Oct 2026Last modified by NVD

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.

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://github.com/php/php-src/security/advisories/GHSA-j3wh-g957-2m85 Vendor AdvisoryExploit
https://github.com/php/php-src/security/advisories/GHSA-j3wh-g957-2m85 Vendor AdvisoryExploit

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Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2026-6103), CISA KEV, FIRST EPSS (scores of 2026-11-14). This page is refreshed as NVD updates the record.