CVE-2025-6491 - CVE House
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Status published Medium CVE-2025-6491

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

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.

Impact Analysis

Refer to official advisory for detailed impact metrics.

Remediation

Ensure systems are updated to the latest vendor-supplied patch levels.

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Credits & Attribution

The following person or organization is credited with identifying this vulnerability, as recorded in the NVD database:

  • Ahmed Lekssays

References

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Affected Vendor

Affected Software

PHP
Vulnerable Versions:
8.1.*, 8.2.*, 8.3.*, 8.4.*

Timeline

Official Publish: July 13th, 2025
Last Modified: November 4th, 2025
Added to House: July 22nd, 2026

CVSS Vectors

V3: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

Weaknesses (CWE)

CWE-476

MITRE ATT&CK TTPs

T1499 Endpoint Denial of Service
Impact
T1499.004 Application or System Exploitation
Impact
T1489 Service Stop
Impact
T1203 Exploitation for Client Execution
Execution
T1190 Exploit Public-Facing Application
Initial Access