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Fencer Vulns
medium 6.5

CVE-2026-91768 json

IPv6 ACL bypass in FastCGI listen.allowed_clients due to partial address comparison (memcmp 12 bytes)

published 2026-09-24 45 d ago modified 2026-10-29 10 d ago also BIT-libphp-2026-91768 , BIT-php-2026-91768 , BIT-php-min-2026-91768 , EUVD-2026-87350 , GHSA-62xp-839h-2637

cvss
6.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 31%
public exploits
0
none known

Summary

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.

Patch / fix

  • bitnami libphp 8.2.34, 8.3.35, 8.4.26, 8.5.11
  • bitnami php 8.2.34, 8.3.35, 8.4.26, 8.5.11
  • bitnami php-min 8.2.34, 8.3.35, 8.4.26, 8.5.11
  • PHP Group PHP 8.2.34, 8.3.35, 8.4.26, 8.5.11
  • php8.2 Debian 12 8.2.34-1~deb12u1
  • php8.4 Debian 13 8.4.26-1~deb13u1
  • php8.4 Debian 14 8.4.26-1

debian advisories DEBIAN-CVE-2026-91768

  • php8.1 Ubuntu 22.04 LTS 8.1.2-1ubuntu2.27
  • php8.3 Ubuntu 24.04 LTS 8.3.6-0ubuntu0.24.04.12
  • php8.5 Ubuntu 26.10 8.5.9-0ubuntu2
  • php8.5 Ubuntu 26.04 LTS 8.5.4-0ubuntu1.4
  • php7.0 Ubuntu Pro 16.04 LTS 7.0.33-0ubuntu0.16.04.16+esm21
  • php7.2 Ubuntu Pro 18.04 LTS 7.2.24-0ubuntu0.18.04.17+esm13
  • php7.4 Ubuntu Pro 20.04 LTS 7.4.3-4ubuntu2.29+esm4

ubuntu advisories UBUNTU-CVE-2026-91768

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • php hummingbird 1 8.5.11-2.hum1
  • php-gd hummingbird 1 8.5.11-2.hum1
  • php-cli hummingbird 1 8.5.11-2.hum1
  • php-dba hummingbird 1 8.5.11-2.hum1
  • php-dbg hummingbird 1 8.5.11-2.hum1
  • php-ffi hummingbird 1 8.5.11-2.hum1
  • php-fpm hummingbird 1 8.5.11-2.hum1
  • php-gmp hummingbird 1 8.5.11-2.hum1

red hat advisories RHSA-2026:70720

  • php7 SLES for SAP 15 SP6, SLES for SAP 15 SP5, SLES for SAP 15 SP4 +7 more 7.4.33-150400.4.81.1
  • php7-fpm SLES for SAP 15 SP6, SLES for SAP 15 SP5, SLES for SAP 15 SP4 +6 more 7.4.33-150400.4.81.1
  • php7-test SLE Module for Package Hub 15 SP7 7.4.33-150400.4.81.2
  • php7-embed SLE Module for Package Hub 15 SP7 7.4.33-150400.4.81.1
  • php7-fastcgi SLES for SAP 15 SP6, SLES for SAP 15 SP5, SLES for SAP 15 SP4 +6 more 7.4.33-150400.4.81.1
  • apache2-mod_php7 SLES for SAP 15 SP6, SLES for SAP 15 SP5, SLES for SAP 15 SP4 +7 more 7.4.33-150400.4.81.1
  • php8 SLES for SAP 15 SP5, SLES for SAP 15 SP4, SLES 15 SP5-LTSS +5 more 8.0.30-150400.4.76.1
  • php8-fpm SLES for SAP 15 SP5, SLES for SAP 15 SP4, SLES 15 SP5-LTSS +5 more 8.0.30-150400.4.76.1

suse advisories SUSE-SU-2026:4853-1SUSE-SU-2026:4651-1SUSE-SU-2026:4603-1SUSE-SU-2026:4602-1SUSE-SU-2026:24158-1

  • php8 openSUSE Leap 16.0 8.4.26-160000.1.1
  • php8-fpm openSUSE Leap 16.0 8.4.26-160000.1.1
  • php8-test openSUSE Leap 16.0 8.4.26-160000.1.1
  • php8-embed openSUSE Leap 16.0 8.4.26-160000.1.1
  • php8-fastcgi openSUSE Leap 16.0 8.4.26-160000.1.1
  • apache2-mod_php8 openSUSE Leap 16.0 8.4.26-160000.1.1
  • php8 openSUSE Tumbleweed 8.5.11-1.1

opensuse advisories openSUSE-SU-2026:22045-1openSUSE-SU-2026:11901-1

  • php AlmaLinux 8 7.4.33-8.module_el8.10.0+4321+cf5fd4bb
  • libzip AlmaLinux 8 1.6.1-1.module_el8.6.0+2750+78feabcb
  • libzip AlmaLinux 8 1.6.1-1.module_el8.6.0+3239+bedf0508
  • libzip AlmaLinux 8 1.6.1-1.module_el8.10.0+3935+28808425
  • php-gd AlmaLinux 8 7.4.33-8.module_el8.10.0+4321+cf5fd4bb
  • php-cli AlmaLinux 8 7.4.33-8.module_el8.10.0+4321+cf5fd4bb
  • php-dba AlmaLinux 8 7.4.33-8.module_el8.10.0+4321+cf5fd4bb
  • php-dbg AlmaLinux 8 7.4.33-8.module_el8.10.0+4321+cf5fd4bb

almalinux advisories ALSA-2026:87080

  • php Rocky Linux 8 7.4.33-8.module+el8.10.0+40393+c071e357
  • libzip Rocky Linux 8 1.6.1-1.module+el8.10.0+1912+72767185
  • libzip Rocky Linux 8 1.6.1-1.module+el8.10.0+1604+6558efc7
  • php-pear Rocky Linux 8 1:1.10.13-1.module+el8.10.0+1912+72767185
  • php-pear Rocky Linux 8 1:1.10.13-1.module+el8.10.0+1605+02e07af7
  • php-pear Rocky Linux 8 1:1.10.13-1.module+el8.10.0+1604+6558efc7
  • php-pecl-rrd Rocky Linux 8 2.0.1-1.module+el8.10.0+1604+6558efc7
  • php-pecl-rrd Rocky Linux 8 2.0.1-1.module+el8.10.0+1912+72767185

rocky linux advisories RLSA-2026:87080

  • php82 Alpine 3.22 8.2.35-r0
  • php83 Alpine 3.23, Alpine 3.22 8.3.36-r0
  • php83 Alpine 3.24 8.3.35-r0
  • php84 Alpine 3.23, Alpine 3.22 8.4.27-r0
  • php84 Alpine 3.24 8.4.26-r0
  • php85 Alpine 3.23 8.5.12-r0
  • php85 Alpine 3.24 8.5.11-r0

alpine advisories ALPINE-CVE-2026-91768

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-91768 updated cvss 6.5

php: php: Access control bypass via partial IPv6 address comparison

  • Red Hat Enterprise Linux 6 php, php-gd, php-cli, php-dba, php-fpm, php-pdo, +21 more
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 7 php, php-gd, php-cli, php-dba, php-fpm, php-pdo, +19 more Red Hat Enterprise Linux 8 php, libzip, php-gd, php-cli, php-dba, php-dbg, +30 more Red Hat Enterprise Linux 9 php, php-gd, php-cli, php-dba, php-dbg, php-ffi, +19 more Red Hat Enterprise Linux 10 php 8.3.33-1.el10_2, php8.4 8.4.24-2.el10
    affected: workaround, no fix available “Fix deferred”
  • Red Hat Enterprise Linux AppStream (v. 8) php 7.4.33-8.module+el8.10.0+25117+30337cca, libzip 1.6.1-1.module+el8.10.0+22485+a3539972, php-gd 7.4.33-8.module+el8.10.0+25117+30337cca, php-cli 7.4.33-8.module+el8.10.0+25117+30337cca, php-dba 7.4.33-8.module+el8.10.0+25117+30337cca, php-dbg 7.4.33-8.module+el8.10.0+25117+30337cca, +28 more
    fixed: vendor fix RHSA-2026:87080
  • Red Hat Hardened Images php 8.5.11-2.hum1, php-gd 8.5.11-2.hum1, php-cli 8.5.11-2.hum1, php-dba 8.5.11-2.hum1, php-dbg 8.5.11-2.hum1, php-ffi 8.5.11-2.hum1, +21 more
    fixed: vendor fix RHSA-2026:70720

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
41 d ago

Exploit prediction

0.38% chance of exploitation in the next 30 days, higher than 31% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 6.5 CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
OSV 3.1 6.5 CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Affected packages

ecosystem package affected fixed in
bitnami libphp
>=8.2.0, <8.2.34
>=8.3.0, <8.3.35
>=8.4.0, <8.4.26
>=8.5.0, <8.5.11
8.2.34
8.3.35
8.4.26
8.5.11
bitnami php
>=8.2.0, <8.2.34
>=8.3.0, <8.3.35
>=8.4.0, <8.4.26
>=8.5.0, <8.5.11
8.2.34
8.3.35
8.4.26
8.5.11
bitnami php-min
>=8.2.0, <8.2.34
>=8.3.0, <8.3.35
>=8.4.0, <8.4.26
>=8.5.0, <8.5.11
8.2.34
8.3.35
8.4.26
8.5.11

Affected products

  • PHP Group PHP

Classification

Weakness
  • CWE-1023 Incomplete Comparison with Missing Factors
Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

The maintainers of php/php-src published their own advisory on GitHub. Reviewed sources take precedence over it.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.