CVSS VectorNVD
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Lifecycle Timeline
5DescriptionNVD
ModSecurity is an open source, cross platform web application firewall (WAF) engine for Apache, IIS and Nginx. Versions prior to 2.9.10 contain a denial of service vulnerability similar to GHSA-859r-vvv8-rm8r/CVE-2025-47947. The sanitiseArg (and sanitizeArg - this is the same action but an alias) is vulnerable to adding an excessive number of arguments, thereby leading to denial of service. Version 2.9.10 fixes the issue. As a workaround, avoid using rules that contain the sanitiseArg (or sanitizeArg) action.
AnalysisAI
ModSecurity versions prior to 2.9.10 contain a denial of service vulnerability in the sanitiseArg and sanitizeArg actions that allows unauthenticated remote attackers to cause service disruption by submitting requests with an excessive number of arguments. This is a network-accessible DoS vulnerability with high impact on availability that affects widely-deployed WAF deployments across Apache, IIS, and Nginx platforms.
Technical ContextAI
ModSecurity is a web application firewall engine that operates as a module for Apache, IIS, and Nginx web servers. The vulnerability exists in the argument sanitization functions (sanitiseArg/sanitizeArg actions) which process HTTP request parameters. The root cause (CWE-1050: Initialization with Hard-Coded Network Resource Configuration Data / similar argument handling flaw) relates to improper bounds checking or resource exhaustion handling when processing a large number of request arguments. When rules containing these actions are triggered, the WAF fails to properly limit or validate the quantity of arguments being processed, allowing an attacker to exhaust memory or processing capacity through argument multiplication attacks, similar to the related CVE-2025-47947 (GHSA-859r-vvv8-rm8r). The vulnerability affects all installations using ModSecurity 2.9.x versions before 2.9.10 on any supported platform (Apache, IIS, Nginx).
RemediationAI
Immediate actions: (1) Upgrade ModSecurity to version 2.9.10 or later (patch available); (2) Apply vendor patches from ModSecurity GitHub repository (https://github.com/SpiderLabs/ModSecurity/releases/tag/v2.9.10); (3) For systems unable to patch immediately, implement workaround by disabling or removing all rules containing sanitiseArg or sanitizeArg actions—identify affected rules in active rulesets (OWASP CRS, vendor-specific rules) and remove or comment them out; (4) Implement rate limiting at upstream load balancer/proxy to limit request argument counts; (5) Monitor for exploitation attempts using WAF logs for requests with unusually high argument counts. Patch path: Update from 2.9.x to 2.9.10+ (appears to be a patch release, not requiring major version upgrade). Vendor advisory and patch details available at ModSecurity GitHub releases.
More from same product – last 7 days
Path traversal in Apache Ignite 2.0.0 through 2.17.0 lets authenticated REST API users read arbitrary files on the serve
Command injection in the shell-quote npm package allows attackers who can influence object-token inputs to inject arbitr
Heap buffer overflow in NGINX Plus and NGINX Open Source ngx_http_rewrite_module allows unauthenticated remote attackers
Code execution via Groovy sandbox bypass in Apache Syncope 3.0 through 3.0.16, 4.0 through 4.0.5, and 4.1.0 allows a hig
Default configurations of Apache Shiro have a session fixation vulnerability. This issue affects Apache Shiro from 1.0
Vendor StatusVendor
Ubuntu
Priority: Medium| Release | Status | Version |
|---|---|---|
| bionic | released | 2.9.2-1ubuntu0.1~esm2 |
| focal | released | 2.9.3-1ubuntu0.1+esm1 |
| jammy | released | 2.9.5-1ubuntu0.1~esm2 |
| noble | released | 2.9.7-1ubuntu0.24.04.1~esm1 |
| oracular | released | 2.9.7-1ubuntu0.24.10.1 |
| plucky | released | 2.9.8-1.1ubuntu0.1 |
| trusty | released | 2.7.7-2ubuntu0.1~esm2 |
| upstream | released | 2.9.10 |
| xenial | released | 2.9.0-1ubuntu0.1~esm2 |
| questing | needs-triage | - |
Debian
Bug #1107196| Release | Status | Fixed Version | Urgency |
|---|---|---|---|
| bullseye | fixed | 2.9.3-3+deb11u4 | - |
| bullseye (security) | fixed | 2.9.3-3+deb11u5 | - |
| bookworm | fixed | 2.9.7-1+deb12u1 | - |
| bookworm (security) | fixed | 2.9.7-1+deb12u1 | - |
| trixie | fixed | 2.9.11-1+deb13u1 | - |
| forky, sid | fixed | 2.9.12-2 | - |
| (unstable) | fixed | 2.9.10-1 | - |
Share
External POC / Exploit Code
Leaving vuln.today
EUVD-2025-16670