CVE-2026-91768
Published:September 25, 2026
Updated:October 09, 2026
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.
Affected Packages
https://github.com/php/php-src.git (GITHUB):
Affected version(s) >=php-8.2.0alpha1 <php-8.2.34Fix Suggestion:
Update to version php-8.2.34https://github.com/php/php-src.git (GITHUB):
Affected version(s) >=php-8.4.0alpha1 <php-8.4.26Fix Suggestion:
Update to version php-8.4.26https://github.com/php/php-src.git (GITHUB):
Affected version(s) >=php-8.3.0alpha1 <php-8.3.35Fix Suggestion:
Update to version php-8.3.35https://github.com/php/php-src.git (GITHUB):
Affected version(s) >=php-8.5.0alpha1 <php-8.5.11Fix Suggestion:
Update to version php-8.5.11Related Resources (1)
Do you need more information?
Contact UsCVSS v4
Base Score:
7.1
Attack Vector
ADJACENT
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
NONE
User Interaction
NONE
Vulnerable System Confidentiality
HIGH
Vulnerable System Integrity
NONE
Vulnerable System Availability
NONE
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
6.5
Attack Vector
ADJACENT
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
NONE
Availability
NONE
Weakness Type (CWE)
Incomplete Comparison with Missing Factors
EPSS
Base Score:
0.56