CVE-2026-6103

medium

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.

References

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

https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-87322

Details

Source: Mitre, NVD

Published: 2026-09-25

Updated: 2026-09-29

Risk Information

CVSS v2

Base Score: 2.1

Vector: CVSS2#AV:L/AC:L/Au:N/C:N/I:P/A:N

Severity: Low

CVSS v3

Base Score: 4.3

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

Severity: Medium

EPSS

EPSS: 0.00167