CVE-2025-31651Public exploitNetwork attack vector

Security constraint bypass via special URL characters

Published Apr 28, 2025 · Updated Feb 26, 2026

URL handling in affected Apache Tomcat 8.5, 9.0, 10.1, and 11.0 releases allows remote attackers to bypass Rewrite Valve rules. RewriteValve matched decoded request paths without first re-encoding literal percent, semicolon, and question-mark characters, confusing URL data with rewrite control syntax. The request is unauthenticated, but impact requires an enabled Rewrite Valve whose rules enforce security constraints; successful requests reach resources those rules were meant to block.

CVSS severity9.8
Critical
EPSS probability4.05%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

URL handling in affected Apache Tomcat 8.5, 9.0, 10.1, and 11.0 releases allows remote attackers to bypass Rewrite Valve rules. RewriteValve matched decoded request paths without first re-encoding literal percent, semicolon, and question-mark characters, confusing URL data with rewrite control syntax. The request is unauthenticated, but impact requires an enabled Rewrite Valve whose rules enforce security constraints; successful requests reach resources those rules were meant to block.

The record

CVE
CVE-2025-31651
Published
Apr 28, 2025
Updated
Feb 26, 2026
Vendor
The Apache Software Foundation
Product
Apache Tomcat
Classifications
CWE-116, CWE-150, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 28, 2025CVE publishedPublication date reported by the CVE source.
  2. Feb 26, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=10.1.0-M1 <=10.1.39
  2. Affected versionversion=11.0.0-M1 <=11.0.5
  3. Affected versionversion=8.5.0 <=8.5.100
  4. Affected versionversion=9.0.0.M1 <=9.0.102

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Apache Software Foundation · Apache Tomcatversion=10.1.0-M1 <=10.1.39; version=11.0.0-M1 <=11.0.5; version=8.5.0 <=8.5.100; version=9.0.0.M1 <=9.0.102

Published CVSS scores

9.8National Vulnerability DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
5.3Amazon LinuxCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
2.7GitHub Advisory DatabaseCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-116Improper Encoding or Escaping of Output
CWE-150Improper Neutralization of Escape, Meta, or Control Sequences
T1190Exploit Public-Facing Application

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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