Skip to content
Fencer Vulns
medium 5.9

CVE-2025-6491 json

NULL Pointer Dereference in PHP SOAP Extension via Large XML Namespace Prefix

published 2025-07-03 16 mo ago modified 2026-09-08 2 mo ago also BIT-libphp-2025-6491 , BIT-php-2025-6491 , BIT-php-min-2025-6491 , EUVD-2025-21276 , GHSA-453j-q27h-5p8x

cvss
5.9
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.1%
EPSS 1.1% chance of exploitation in 30 days, percentile 66%
public exploits
0
none known

Summary

In PHP versions:8.1.* before 8.1.33, 8.2.* before 8.2.29, 8.3.* before 8.3.23, 8.4.* before 8.4.10 when parsing XML data in SOAP extensions, overly large (>2Gb) XML namespace prefix may lead to null pointer dereference. This may lead to crashes and affect the availability of the target server.

Patch / fix

  • bitnami libphp 8.1.33, 8.2.29, 8.3.23, 8.4.10
  • bitnami php 8.1.33, 8.2.29, 8.3.23, 8.4.10
  • bitnami php-min 8.1.33, 8.2.29, 8.3.23, 8.4.10
  • PHP Group PHP 8.1.33, 8.2.29, 8.3.23, 8.4.10
  • php8.2 Debian 12 8.2.29-1~deb12u1
  • php8.4 Debian 14, Debian 13 8.4.10-1

debian advisories DEBIAN-CVE-2025-6491

  • php8.1 Ubuntu 22.04 LTS 8.1.2-1ubuntu2.22
  • php8.3 Ubuntu 24.04 LTS 8.3.6-0ubuntu0.24.04.5
  • php8.4 Ubuntu 25.10 8.4.11-1ubuntu1
  • php7.0 Ubuntu Pro 16.04 LTS 7.0.33-0ubuntu0.16.04.16+esm16
  • php7.2 Ubuntu Pro 18.04 LTS 7.2.24-0ubuntu0.18.04.17+esm9
  • php7.4 Ubuntu Pro 20.04 LTS 7.4.3-4ubuntu2.29+esm1

ubuntu advisories UBUNTU-CVE-2025-6491

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 RHEL 8 7.4.33-3.module+el8.10.0+23902+d3c8dd8f
  • libzip RHEL 8 1.6.1-1.module+el8.10.0+22485+a3539972
  • php-gd RHEL 8 7.4.33-3.module+el8.10.0+23902+d3c8dd8f
  • php-cli RHEL 8 7.4.33-3.module+el8.10.0+23902+d3c8dd8f
  • php-dba RHEL 8 7.4.33-3.module+el8.10.0+23902+d3c8dd8f
  • php-dbg RHEL 8 7.4.33-3.module+el8.10.0+23902+d3c8dd8f
  • php-ffi RHEL 8 7.4.33-3.module+el8.10.0+23902+d3c8dd8f
  • php-fpm RHEL 8 7.4.33-3.module+el8.10.0+23902+d3c8dd8f

red hat advisories RHSA-2026:2470RHSA-2026:1412RHSA-2026:1409RHSA-2025:23309

  • php8 SLE Module for Web and Scripting 15 SP6, openSUSE Leap 15.6 8.2.29-150600.3.19.1
  • php8-fpm SLE Module for Web and Scripting 15 SP6, openSUSE Leap 15.6 8.2.29-150600.3.19.1
  • php8-test SLE Module for Web and Scripting 15 SP6, openSUSE Leap 15.6 8.2.29-150600.3.19.2
  • php8-embed SLE Module for Web and Scripting 15 SP6, openSUSE Leap 15.6 8.2.29-150600.3.19.1
  • php8-fastcgi SLE Module for Web and Scripting 15 SP6, openSUSE Leap 15.6 8.2.29-150600.3.19.1
  • apache2-mod_php8 SLE Module for Web and Scripting 15 SP6, openSUSE Leap 15.6 8.2.29-150600.3.19.1
  • php7 SLES for SAP 15 SP5, SLES for SAP 15 SP4, SLES 15 SP5-LTSS +6 more 7.4.33-150400.4.51.1
  • php7-fpm SLES for SAP 15 SP5, SLES for SAP 15 SP4, SLES 15 SP5-LTSS +5 more 7.4.33-150400.4.51.1

suse advisories SUSE-SU-2025:02474-1SUSE-SU-2025:02473-1SUSE-SU-2025:02463-1SUSE-SU-2025:02462-1

  • php8 openSUSE Tumbleweed 8.4.10-1.1

opensuse advisories openSUSE-SU-2025:15340-1

  • php AlmaLinux 8 7.4.33-3.module_el8.10.0+4114+3b36c618
  • libzip AlmaLinux 8 1.6.1-1.module_el8.6.0+3239+bedf0508
  • libzip AlmaLinux 8 1.6.1-1.module_el8.6.0+2750+78feabcb
  • libzip AlmaLinux 8 1.6.1-1.module_el8.10.0+3935+28808425
  • php-gd AlmaLinux 8 7.4.33-3.module_el8.10.0+4114+3b36c618
  • php-cli AlmaLinux 8 7.4.33-3.module_el8.10.0+4114+3b36c618
  • php-dba AlmaLinux 8 7.4.33-3.module_el8.10.0+4114+3b36c618
  • php-dbg AlmaLinux 8 7.4.33-3.module_el8.10.0+4114+3b36c618

almalinux advisories ALSA-2026:2470ALSA-2026:1409ALSA-2026:1412ALSA-2025:23309

  • libzip Rocky Linux 8 1.6.1-1.module+el8.10.0+1912+72767185
  • 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-pecl-rrd Rocky Linux 8 2.0.1-1.module+el8.4.0+414+2e7afcdd
  • php-pecl-rrd Rocky Linux 8 2.0.1-1.module+el8.10.0+1912+72767185
  • php-pecl-zip Rocky Linux 8 1.18.2-1.module+el8.10.0+1912+72767185
  • php-pecl-apcu Rocky Linux 8 5.1.18-1.module+el8.10.0+1912+72767185
  • php-pecl-xdebug Rocky Linux 8 2.9.5-1.module+el8.10.0+1912+72767185

rocky linux advisories RLSA-2026:2470RLSA-2026:1409RLSA-2026:1412RLSA-2025:23309

  • php81 Alpine 3.19 8.1.33-r0
  • php82 Alpine 3.22 8.2.29-r0
  • php83 Alpine 3.24, Alpine 3.23, Alpine 3.22 8.3.23-r0
  • php84 Alpine 3.22 8.4.10-r0
  • php84 Alpine 3.24, Alpine 3.23 8.4.9-r0

alpine advisories ALPINE-CVE-2025-6491

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

  • php Azure Linux 3.0 8.3.23-1
  • php CBL-Mariner 2.0 8.1.33-1

azure linux advisories AZL-65118AZL-65127

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

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-2025-6491 updated cvss 5.9

php: NULL Pointer Dereference in PHP SOAP Extension via Large XML Namespace Prefix

  • Red Hat Enterprise Linux 6 php, php-gd, php-cli, php-dba, php-fpm, php-pdo, +20 more Red Hat Enterprise Linux 7 php, php-gd, php-cli, php-dba, php-fpm, php-pdo, +18 more Red Hat Enterprise Linux 9 php, php-gd, php-cli, php-dba, php-dbg, php-ffi, +18 more Red Hat Enterprise Linux 10 php
    affected: workaround, no fix available “Currently, no mitigation is currently available for this vulnerability.”
  • Red Hat Enterprise Linux AppStream (v. 8) php 7.4.33-3.module+el8.10.0+23902+d3c8dd8f, php 8.2.30-1.module+el8.10.0+23848+33d54484, libzip 1.6.1-1.module+el8.10.0+22485+a3539972, libzip 1.7.3-1.module+el8.10.0+20770+a5eca186, php-gd 7.4.33-3.module+el8.10.0+23902+d3c8dd8f, php-gd 8.2.30-1.module+el8.10.0+23848+33d54484, +60 more
    fixed: vendor fix “Currently, no mitigation is currently available for this vulnerability.” RHSA-2026:2470
  • Red Hat Enterprise Linux AppStream (v. 9) php 8.2.30-1.module+el9.7.0+23849+7b831f17, php 8.3.26-1.module+el9.7.0+23549+c13c2ce3, php-gd 8.2.30-1.module+el9.7.0+23849+7b831f17, php-gd 8.3.26-1.module+el9.7.0+23549+c13c2ce3, php-cli 8.2.30-1.module+el9.7.0+23849+7b831f17, php-cli 8.3.26-1.module+el9.7.0+23549+c13c2ce3, +53 more
    fixed: vendor fix “Currently, no mitigation is currently available for this vulnerability.” RHSA-2026:1409

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
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
15 mo ago

Exploit prediction

1.12% chance of exploitation in the next 30 days, higher than 66% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/php/php-src/security/advisories/GHSA-453j-q27h-5p8x referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
OSV 3.1 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
bitnami libphp
<8.1.33
>=8.2.0, <8.2.29
>=8.3.0, <8.3.23
>=8.4.0, <8.4.10
8.1.33
8.2.29
8.3.23
8.4.10
bitnami php
<8.1.33
>=8.2.0, <8.2.29
>=8.3.0, <8.3.23
>=8.4.0, <8.4.10
8.1.33
8.2.29
8.3.23
8.4.10
bitnami php-min
<8.1.33
>=8.2.0, <8.2.29
>=8.3.0, <8.3.23
>=8.4.0, <8.4.10
8.1.33
8.2.29
8.3.23
8.4.10

Affected products

  • PHP Group PHP

Classification

Weakness
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.