Vulnerability in Apache Tomcat

CVE-2025-31651

Improper Neutralization of Escape, Meta, or Control Sequences vulnerability in Apache Tomcat. For a subset of unlikely rewrite rule configurations, it was possible for a specially crafted request to bypass some rewrite rules. If those rewrite rules effectively enforced security constraints, those constraints could be bypassed. This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.5, from 10.1.0-M1 through 10.1.39, from 9.0.0.M1 through 9.0.102. The following versions were EOL at the time the CVE was created but are known to be affected: 8.5.0 though 8.5.100. Other, older, EOL versions may also be affected. Users are recommended to upgrade to version [FIXED_VERSION], which fixes the issue.

EPSS: 0.043 (90.1th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2025-31651?
CVE-2025-31651 is a critical-severity vulnerability in Apache Tomcat, classified under Improper Encoding or Escaping of Output. CVSS score: 9.8/10. Published 2025-04-28.
How severe is CVE-2025-31651?
Critical severity. CVSS v3 base score is 9.8 out of 10.
Is CVE-2025-31651 known to be exploited?
11 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.