CVE-2025-52891Network attack vector

Service crash via empty XML node value

Published Jul 2, 2025 · Updated Jul 2, 2025

Improper input validation in ModSecurity 2.9.8 through 2.9.10 allows remote attackers to crash the WAF with an empty XML tag. The mod_security2 XML-to-arguments path calls strlen() on a null node value when libxml2 represents an empty element without text, causing a segmentation fault. Exposure requires SecParseXmlIntoArgs set to On or OnlyArgs and an application/xml request reaching the module; the default Off setting is not affected.

CVSS severity6.5
Medium
EPSS probability0.36%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Improper input validation in ModSecurity 2.9.8 through 2.9.10 allows remote attackers to crash the WAF with an empty XML tag. The mod_security2 XML-to-arguments path calls strlen() on a null node value when libxml2 represents an empty element without text, causing a segmentation fault. Exposure requires SecParseXmlIntoArgs set to On or OnlyArgs and an application/xml request reaching the module; the default Off setting is not affected.

The record

CVE
CVE-2025-52891
Published
Jul 2, 2025
Updated
Jul 2, 2025
Vendor
OWASP ModSecurity
Product
ModSecurity
Classifications
CWE-20, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 2, 2025CVE publishedPublication date reported by the CVE source.
  2. Jul 2, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=>= 2.9.8, < 2.9.11

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

OWASP ModSecurity · ModSecurityversion=>= 2.9.8, < 2.9.11

Published CVSS scores

6.5GitHubCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-20Improper Input Validation
T1499.004Application or System Exploitation DoS

Public exploit references

No public exploit references are available in this record.

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

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo