CVE-2026-91768
IPv6 ACL bypass in FastCGI listen.allowed_clients due to partial address comparison (memcmp 12 bytes)
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.
No summary for this CVE yet.
CVSS Vector Breakdown
Exploitability
AV:AAttack VectorAdjacent
AC:LAttack ComplexityLow
PR:NPrivileges RequiredNone
UI:NUser InteractionNone
Scope
S:UScopeUnchanged
Impact
C:HConfidentialityHigh
I:NIntegrityNone
A:NAvailabilityNone
Weaknesses
Affected Products
PHP Group
oss-projectaka php, pear
Exploitability
No known exploits, KEV entries, or remediation guidance available for this vulnerability yet.
References
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