CVE-2026-6103

Phar TAR phar_tar_number() Integer Overflow - Archive Entry Injection

Published Sep 25, 2026 CVSS 3.1 · 4.3 Medium EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Debian DLA Debian DLA DLA-4819-1 php8.2 security update
Debian DSA Debian DSA DSA-6514-1 php8.4 security update
Ubuntu USN Ubuntu USN USN-8936-1 PHP vulnerabilities
History
Type Values Removed Values Added
First Time appeared Php
Php php
CPEs cpe:2.3:a:php:php:*:*:*:*:*:*:*:*
Vendors & Products Php
Php php
Type Values Removed Values Added
First Time appeared Php Group
Php Group php
Vendors & Products Php Group
Php Group php
Type Values Removed Values Added
First Time appeared Redhat
Redhat hummingbird
CPEs cpe:/a:redhat:hummingbird:1
Vendors & Products Redhat
Redhat hummingbird
References
Metrics threat_severity

None

threat_severity

Moderate

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
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.
Title Phar TAR phar_tar_number() Integer Overflow - Archive Entry Injection
Weaknesses CWE-190
References
Metrics cvssV3_1

{'score': 4.3, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
php
Published
Updated
Sep 25, 2026, 8:41 PM
Reserved
Apr 11, 2026, 4:13 AM
Status
Analyzed
Published
Sep 25, 2026, 9:17 PM
Modified
Oct 23, 2026, 2:07 PM
Severity
Moderate
Public date
Sep 25, 2026, 8:08 PM