CVE-2026-6103

CVE Details

Release Date:	2026-09-25
Impact:	Moderate	What is this?

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.

See more information about CVE-2026-6103 from MITRE CVE dictionary and NIST NVD

NOTE: The following CVSS metrics and score provided are preliminary and subject to review.

CVSS v3 metrics

Base Score:	4.3
Vector String:	CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
Version:	3.1
Attack Vector:	Local
Attack Complexity:	Low
Privileges Required:	None
User Interaction:	None
Scope:	Changed
Confidentiality Impact:	None
Integrity Impact:	Low
Availability Impact:	None

Errata information

Platform	Errata	Release Date
Oracle Linux version 8 (libzip)	ELSA-2026-87080	2026-10-21
Oracle Linux version 8 (php)	ELSA-2026-87080	2026-10-21
Oracle Linux version 8 (php-pear)	ELSA-2026-87080	2026-10-21
Oracle Linux version 8 (php-pecl-apcu)	ELSA-2026-87080	2026-10-21
Oracle Linux version 8 (php-pecl-rrd)	ELSA-2026-87080	2026-10-21
Oracle Linux version 8 (php-pecl-xdebug)	ELSA-2026-87080	2026-10-21
Oracle Linux version 8 (php-pecl-zip)	ELSA-2026-87080	2026-10-21