PHP<8.x: NPD via XML NS Prefix in SOAP
CVE-2025-6491 Published on July 13, 2025
NULL Pointer Dereference in PHP SOAP Extension via Large XML Namespace Prefix
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.
Vulnerability Analysis
CVE-2025-6491 can be exploited with network access, and does not require authorization privileges or user interaction. This vulnerability is consided to have a high level of attack complexity. Public availability of a proof of concept (POC) exploit exists for CVE-2025-6491. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity, and a high impact on availability.
Weakness Type
NULL Pointer Dereference
A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit. NULL pointer dereference issues can occur through a number of flaws, including race conditions, and simple programming omissions.
Products Associated with CVE-2025-6491
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Affected Versions
PHP Group PHP:- Version 8.1.* and below 8.1.33 is affected.
- Version 8.2.* and below 8.2.29 is affected.
- Version 8.3.* and below 8.3.23 is affected.
- Version 8.4.* and below 8.4.10 is affected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.