Description
ModSecurity is an open source, cross platform web application firewall (WAF) engine for Apache, IIS and Nginx. From 3.0.5 until 3.0.17, the PCRE2 implementation of @rxGlobal in src/utils/regex.cc converts pcre2_match match-limit errors into an ordinary no-match result instead of propagating a non-OK RegexResult. When attacker-controlled input exhausts SecPcreMatchLimit, rules that rely on MSC_PCRE_LIMITS_EXCEEDED or its TX compatibility indicator do not run, so a request that should be rejected can pass through the WAF. The issue affects PCRE2 deployments that use @rxGlobal with a limit-exhaustible expression and a compensating rule; it is not a universal WAF bypass. This issue is fixed in version 3.0.17.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| owasp-modsecurity | ModSecurity | >= 3.0.5, < 3.0.17 | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | modsecurity | No fix yet | — |
| Debian 13 | modsecurity | No fix yet | — |
| Debian 12 | modsecurity | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | modsecurity | No fix yet | — |
| Ubuntu 26.04 LTS | modsecurity | No fix yet | — |
| Ubuntu 24.04 LTS | modsecurity | No fix yet | — |
| Ubuntu 22.04 LTS | modsecurity | No fix yet | — |
| Ubuntu 20.04 LTS | modsecurity | No fix yet | — |
Advisories 1
- WID-SEC-2026-3666 OWASP ModSecurity: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 9, 2026