CVE-2026-61619
OWASP CRS: ReDoS in shared unix-shell-evasion regex-assembly include (12 RCE rules) - PCRE2 backtracking-limit exhaustion causes detection bypass and CPU DoS
The OWASP core rule set (CRS) is a set of generic attack detection rules for use with compatible web application firewalls. Prior to versions 3.3.10, 4.25.1, and 4.28.0, regular-expression denial of service (ReDoS) affects a shared regex-assembly include used to build 12 Unix RCE detection rules in CRS v4, and the same ambiguous pattern was present in the manually-assembled regexes in 4 rules in CRS v3.3. With a single, unauthenticated, crafted request, the generated pattern drives PCRE2 past its backtracking limit. When PCRE2 exceeds that limit, the @rx operator returns an error rather than a match result, which results in detection bypass and CPU denial of service. This issue has been patched in versions 3.3.10, 4.25.1, and 4.28.0.
Fixes and workarounds
No remediation reported in collected sources.
Missing remediation information is not evidence that no patch exists.
Affected products and versions
| Product | Versions | Authority |
|---|---|---|
| coreruleset coreruleset |
< 3.3.10 (affected) < 4.25.1 (affected) < 4.28.0 (affected) |
CNA: GitHub_M |
Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.
CVSS assessments
| Version / score | Vector | Authority |
|---|---|---|
| 4.0 / 8.8 high |
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N | CNA: GitHub_M |
Exploit evidence
No exploit evidence in collected sources. This is not proof of no exploitation.
References
- https://github.com/coreruleset/coreruleset/security/advisories/GHSA-f5qm-3h4p-8qhgCNA: GitHub_M · x_refsource_CONFIRM
- https://github.com/coreruleset/coreruleset/commit/4665b6d7a79a81aa8a802ef3c901d69491c009a4CNA: GitHub_M · x_refsource_MISC
- https://github.com/coreruleset/coreruleset/commit/6083611d00291e85ab7b587e96577deb53ed9cacCNA: GitHub_M · x_refsource_MISC
- https://github.com/coreruleset/coreruleset/commit/e3b612a909532dcc8d056c01ac04b31117b71505CNA: GitHub_M · x_refsource_MISC
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