PHP security advisory

NULL pointer dereference in SoapVar with oversized qualified names

CVE-2025-6491Medium 5.9 Published ext/soap

Passing a fully qualified name larger than 2 GB to SoapVar causes a NULL pointer dereference and crash when PHP is linked against libxml2 older than 2.13.

Affected versions

BranchAffectedFixed in
PHP 8.4< 8.4.108.4.10
PHP 8.3< 8.3.238.3.23
PHP 8.2< 8.2.298.2.29
PHP 8.1< 8.1.338.1.33

Older branches: not assessed

Exploitation conditions

  • Builds linked against libxml2 < 2.13

Remediation

Upgrade to 8.1.33, 8.2.29, 8.3.23, 8.4.10 or a later release of your branch. If your branch is end-of-life, move to a supported branch. Distribution packages may carry a backported fix under an older version number; confirm with your vendor's security tracker.

A version number alone cannot prove patch status. Linux distributions and hosting providers often backport security fixes without changing the version. Check your vendor’s changelog.

Severity scores

CVSSSourceVector
5.9 v3.1CNA—

References

Data provenance

Secondary sources · pending primary verification

Last reviewed: Oct 24, 2026 · Source

Notes: Score from a distribution tracker.