CVE-2025-6491 — MEDIUM (5.9)

Vulnerability Description

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.

CVSS Score

5.9

MEDIUM

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack Vector

NETWORK

Attack Complexity

HIGH

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality

NONE

Integrity

NONE

Availability

HIGH

Affected Products

Vendor	Product	Versions
Php	Php	>= 8.1.0, < 8.1.33

Related Weaknesses (CWE)

CWE-476

References

https://github.com/php/php-src/security/advisories/GHSA-453j-q27h-5p8xExploitVendor Advisory
http://www.openwall.com/lists/oss-security/2025/07/11/4
https://lists.debian.org/debian-lts-announce/2025/07/msg00017.html
https://github.com/php/php-src/security/advisories/GHSA-453j-q27h-5p8xExploitVendor Advisory

FAQ

What is CVE-2025-6491?

CVE-2025-6491 is a vulnerability with a CVSS score of 5.9 (MEDIUM). 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 p...

How severe is CVE-2025-6491?

CVE-2025-6491 has been rated MEDIUM with a CVSS base score of 5.9/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2025-6491?

Check the references section above for vendor advisories and patch information. Affected products include: Php Php.