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CVE-2025-6491

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

Medium5.9EPSS 1.1%
Published
Updated
Reserved
Assigned by
php

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.

Scores

CVSS scores of CVE-2025-6491, by who scored it
Scored byCVSSScoreVector
phpCNA (assigner)3.1Medium5.9CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
NVDNVD · Modified3.1Medium5.9CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS (exploitation in 30 days)
1.1% · top 34% of all CVEs (5 Nov 2026)
CISA SSVC
Exploitation: poc · Automatable: no · Technical impact: partial
Loading the EPSS history…

The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 5.9.

Weakness

Affected products

  • PHP Group · PHP

    • affected 8.1.* – < 8.1.33
    • affected 8.2.* – < 8.2.29
    • affected 8.3.* – < 8.3.23
    • affected 8.4.* – < 8.4.10

References (3)

Sources

The same CVE in the primary databases and aggregators, to check against.

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Record last updated .