# 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

Status: published. Published: 2026-11-11. Updated: 2026-11-11.

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.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- coreruleset / coreruleset: < 3.3.10 (affected); < 4.25.1 (affected); < 4.28.0 (affected). Source: CNA: GitHub_M

## Severity and prioritization

- CVSS 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; source: CNA: GitHub_M

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: Not available

- Weaknesses: CWE-1333

## 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-8qhg (CNA: GitHub_M; x_refsource_CONFIRM)

- https://github.com/coreruleset/coreruleset/commit/4665b6d7a79a81aa8a802ef3c901d69491c009a4 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/coreruleset/coreruleset/commit/6083611d00291e85ab7b587e96577deb53ed9cac (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/coreruleset/coreruleset/commit/e3b612a909532dcc8d056c01ac04b31117b71505 (CNA: GitHub_M; x_refsource_MISC)

## Provenance

- CNA: GitHub_M: https://www.cve.org/CVERecord?id=CVE-2026-61619; retrieved 2026-11-11; source updated 2026-11-11

Revision: 00dedd6591859daf508d31596f235240ec7c2d278621e78d0260d6d067ae88ba

Canonical: https://y2.dev/cve/CVE-2026-61619

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