CVE-2026-6103: Phar TAR phar_tar_number() Integer Overflow - Archive Entry Injection
Fixed (Integer overflow in phartarnumber() allowing TAR archive entry injection). (CVE-2026-6103)
Other sources
Phar TAR phartarnumber() Integer Overflow - Archive Entry Injection
— Microsoft
phartarnumber() parses the octal size field of a TAR header into a uint32t 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.
— NVD
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 8.4.26 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 8.3.35-1