CVE-2026-6103
Published: September 26, 2026Last modified: September 26, 2026
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.
Severity score breakdown
| Parameter | Value |
|---|---|
| Base score | 4.3 |
| Attack Vector | LOCAL |
| Attack complexity | LOW |
| Privileges required | NONE |
| User interaction | NONE |
| Scope | CHANGED |
| Confidentiality | NONE |
| Integrity impact | LOW |
| Availability impact | NONE |
| Vector | CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N |
Status
| Product | Release | Package | Status |
|---|---|---|---|
| Alpaquita Linux | 23 LTS | php81 | Unknown (8.1.19-r0) |
| 25 LTS | php83 | Fixed (8.3.35-r0) | |
| Stream | php83 | Fixed (8.3.35-r0) |