Process crash via oversized SOAP namespace prefix
Published Jul 13, 2025 · Updated Nov 4, 2025
Null pointer dereference in PHP SOAP before 8.1.33, 8.2.29, 8.3.23, and 8.4.10 allows remote attackers to crash PHP processes. For names longer than 2 GB, libxml before 2.13 leaves the XML node name null after xmlNodeSetName(), and PHP's serialize_zval() later passes it to strcmp(). Exploitation requires the SOAP extension and application code that builds a SoapVar qualified name from remote, attacker-controlled SOAP data; the resulting segmentation fault terminates the PHP process.
Summary
What happened
Null pointer dereference in PHP SOAP before 8.1.33, 8.2.29, 8.3.23, and 8.4.10 allows remote attackers to crash PHP processes. For names longer than 2 GB, libxml before 2.13 leaves the XML node name null after xmlNodeSetName(), and PHP's serialize_zval() later passes it to strcmp(). Exploitation requires the SOAP extension and application code that builds a SoapVar qualified name from remote, attacker-controlled SOAP data; the resulting segmentation fault terminates the PHP process.
The record
- CVE
- CVE-2025-6491
- Published
- Jul 13, 2025
- Updated
- Nov 4, 2025
- Vendor
- The PHP Group
- Product
- PHP
- Classifications
- CWE-476, T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jul 13, 2025CVE publishedPublication date reported by the CVE source.
- Nov 4, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=8.1.* <8.1.33
- Affected versionversion=8.2.* <8.2.29
- Affected versionversion=8.3.* <8.3.23
- Affected versionversion=8.4.* <8.4.10
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- Upstream oversized SoapVar qualified-name proof of conceptproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
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