CVE-2026-91768
Publication date 25 September 2026
Last updated 7 October 2026
Ubuntu priority
Description
The IPv6 branch of the FastCGI client access check compares only the first 12 bytes of a 16-byte IPv6 address, so listen.allowed_clients matches on a /96 prefix instead of the exact address. An attacker who can source an address sharing the first 96 bits with an allowed one passes the check and reaches the FastCGI endpoint.
Status
| Package | Ubuntu Release | Status |
|---|---|---|
| php5 | 26.04 LTS resolute | Not in release |
| 24.04 LTS noble | Not in release | |
| 22.04 LTS jammy | Not in release | |
| 14.04 LTS trusty |
Vulnerable
|
|
| php7.0 | 26.04 LTS resolute | Not in release |
| 24.04 LTS noble | Not in release | |
| 22.04 LTS jammy | Not in release | |
| 16.04 LTS xenial |
Vulnerable
|
|
| php7.2 | 26.04 LTS resolute | Not in release |
| 24.04 LTS noble | Not in release | |
| 22.04 LTS jammy | Not in release | |
| 18.04 LTS bionic |
Vulnerable
|
|
| php7.4 | 26.04 LTS resolute | Not in release |
| 24.04 LTS noble | Not in release | |
| 22.04 LTS jammy | Not in release | |
| 20.04 LTS focal |
Vulnerable
|
|
| php8.1 | 26.04 LTS resolute | Not in release |
| 24.04 LTS noble | Not in release | |
| 22.04 LTS jammy |
Vulnerable
|
|
| php8.3 | 26.04 LTS resolute | Not in release |
| 24.04 LTS noble |
Vulnerable
|
|
| 22.04 LTS jammy | Not in release | |
| php8.5 | 26.04 LTS resolute |
Vulnerable
|
| 24.04 LTS noble | Not in release | |
| 22.04 LTS jammy | Not in release |
Notes
sbeattie
PEAR issues should go against php-pear as of xenial PEAR issues should go against php-pear as of xenial
Severity score breakdown
CVSS version: CVSS v3.0
Base score
6.5 · Medium
Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N