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Medium

Apache Tomcat Denial of Service via invalid HTTP priority header

  • Disclosed: 28.04.2025
  • Updated: 11.10.2026 13:20

Improper Input Validation vulnerability in Apache Tomcat. Incorrect error handling for some invalid HTTP priority headers resulted in incomplete clean-up of the failed request which created a memory leak. A large number of such requests could trigger an OutOfMemoryException resulting in a denial of service.

This issue affects Apache Tomcat: from 9.0.76 through 9.0.102, from 10.1.10 through 10.1.39, from 11.0.0-M2 through 11.0.5. The following versions were EOL at the time the CVE was created but are known to be affected: 8.5.90 though 8.5.100.

Users are recommended to upgrade to version 9.0.104, 10.1.40 or 11.0.6 which fix the issue.

Affected software

Click a technology to see all vulnerabilities affecting it.

PlatformPackageVulnerable versionsFixed in
Java / Kotlin (Maven) org.apache.tomcat.embed:tomcat-embed-core >= 9.0.76, < 9.0.104, >= 10.1.10, < 10.1.40, >= 11.0.0-M2, < 11.0.6, >= 8.5.0, <= 8.5.100 9.0.104, 10.1.40, 11.0.6
Java / Kotlin (Maven) org.apache.tomcat:tomcat-coyote >= 9.0.76, < 9.0.104, >= 10.1.10, < 10.1.40, >= 11.0.0-M2, < 11.0.6, >= 8.5.0, <= 8.5.100 9.0.104, 10.1.40, 11.0.6

References

CVSS score -
CVSS vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U
Weakness (CWE)
CWE-459, CWE-460
Platform
Java / Kotlin (Maven)
Package
org.apache.tomcat.embed:tomcat-embed-core, org.apache.tomcat:tomcat-coyote
Disclosed
28.04.2025
Updated
11.10.2026 13:20

Sources and licenses

OSV / GitHub Advisory Database - GHSA-3p2h-wqq4-wf4h - CC BY 4.0

Vulnerability history: org.apache.tomcat.embed:tomcat-embed-core

All published vulnerabilities of this package (Java / Kotlin (Maven)), newest first. Shows whether this is a one-off slip or a package that needs watching.

All (77) in the archive
Total entries
77
First → latest
10.2018 08.2026
Without a fix
0
Exploited in attacks
5

Severity breakdown

  • Critical 11
  • High 36
  • Medium 25
  • Low 5

Disclosures per year

Severity:
  1. Apache Tomcat's DIGEST authenticator has an Authentication Bypass by Capture-replay vulnerability
    Critical · 9.8 CVE-2026-65905 >= 11.0.0-M1, < 11.0.25, >= 10.1.0-M1, < 10.1.58, >= 9.0.0.M1, < 9.0.121, >= 8.5.0, <= 8.5.100, >= 7.0.30, <= 7.0.109 11.0.25, 10.1.58, 9.0.121
  2. Apache Tomcat has an Improper Access Control, Incorrect Authorization vulnerability
    Critical · 9.1 CVE-2026-65182 >= 11.0.0-M1, < 11.0.25, >= 10.1.0-M1, < 10.1.58, >= 9.0.0-M1, < 9.0.121, >= 8.5.0, <= 8.5.100, >= 7.0.0, <= 7.0.109 11.0.25, 10.1.58, 9.0.121
  3. Apache Tomcat's FORM authentication process has an Incorrect Authorization vulnerability
    Critical · 9.1 CVE-2026-68525 >= 11.0.0-M1, < 11.0.25, >= 10.1.0-M1, < 10.1.58, >= 9.0.0-M1, < 9.0.121, >= 8.5.0, <= 8.5.100, >= 7.0.0, <= 7.0.109 11.0.25, 10.1.58, 9.0.121
  4. Apache Tomcat: Unbounded read in WebDAV LOCK and PROPFIND handling
    High · 7.5 CVE-2026-41284 < 9.0.118, >= 10.1.0-M1, < 10.1.55, >= 11.0.0-M1, < 11.0.22 9.0.118, 10.1.55, 11.0.22
  5. Apache Tomcat - Digest authenticator will authenticate any unknown user
    Critical · 9.8 CVE-2026-43512 < 9.0.118, >= 10.1.0-M1, < 10.1.55, >= 11.0.0-M1, < 11.0.22 9.0.118, 10.1.55, 11.0.22
  6. Apache Tomcat: LockOutRealm treats user names as case-sensitive
    High · 7.5 CVE-2026-43513 < 9.0.118, >= 10.1.0-M1, < 10.1.55, >= 11.0.0-M1, < 11.0.22 9.0.118, 10.1.55, 11.0.22
  7. Apache Tomcat - Security constraints not correctly applied
    Critical · 9.1 CVE-2026-43515 < 9.0.118, >= 10.1.0-M1, < 10.1.55, >= 11.0.0-M1, < 11.0.22 9.0.118, 10.1.55, 11.0.22
  8. Apache Tomcat - WebSocket authentication header exposure
    High · 7.3 CVE-2026-42498 < 9.0.118, >= 10.1.0-M1, < 10.1.55, >= 11.0.0-M1, < 11.0.22 9.0.118, 10.1.55, 11.0.22
  9. Apache Tomcat - HTTP/2 request headers not validated
    Critical · 9.8 CVE-2026-41293 >= 8.5.0, < 9.0.118, >= 10.1.0-M1, < 10.1.55, >= 11.0.0-M1, < 11.0.22 9.0.118, 10.1.55, 11.0.22
  10. Apache Tomcat vulnerable to Insertion of Sensitive Information into Log File
    High · 7.5 CVE-2026-34487 >= 9.0.13, < 9.0.117, >= 10.1.0-M1, < 10.1.54, >= 11.0.0-M1, < 11.0.21 9.0.117, 10.1.54, 11.0.21
  11. Apache Tomcat has an Improper Encoding or Escaping of Output vulnerability in the JsonAccessLogValve
    High · 7.5 CVE-2026-34483 >= 9.0.40, < 9.0.116, >= 10.1.0-M1, < 10.1.54, >= 11.0.0-M1, < 11.0.21 9.0.116, 10.1.54, 11.0.21
  12. Apache Tomcat has an HTTP Request/Response Smuggling vulnerability
    High · 7.5 CVE-2026-24880 >= 7.0.0, < 9.0.116, >= 10.1.0-M1, < 10.1.52, >= 11.0.0-M1, < 11.0.20 9.0.116, 10.1.52, 11.0.20
  13. Apache Tomcat: Configured cipher preference order not preserved
    High · 7.5 CVE-2026-29129 >= 9.0.114, < 9.0.116, >= 10.1.51, < 10.1.53, >= 11.0.16, < 11.0.20 9.0.116, 10.1.53, 11.0.20
  14. Apache Tomcat has an Improper Input Validation vulnerability
    High · 7.5 CVE-2026-24734 >= 11.0.0-M1, < 11.0.18, >= 10.1.0-M7, < 10.1.52, >= 9.0.83, < 9.0.115 11.0.18, 10.1.52, 9.0.115
  15. Apache Tomcat Vulnerable to Relative Path Traversal
    High · 7.5 CVE-2025-55752 >= 11.0.0-M1, < 11.0.11, >= 10.1.0-M1, < 10.1.45, >= 9.0.0-M11, < 9.0.109, >= 8.5.6, <= 8.5.100 11.0.11, 10.1.45, 9.0.109
  16. Apache Tomcat Improper Resource Shutdown or Release vulnerability
    High · 7.5 CVE-2025-48989 >= 11.0.0-M1, < 11.0.10, >= 10.1.0-M1, < 10.1.44, >= 9.0.0.M1, < 9.0.108 11.0.10, 10.1.44, 9.0.108
  17. Apache Tomcat Coyote vulnerable to Denial of Service via excessive HTTP/2 streams
    High · 7.5 CVE-2025-53506 >= 8.5.0, <= 8.5.100, >= 9.0.0.M1, < 9.0.107, >= 10.1.0-M1, < 10.1.43, >= 11.0.0-M1, < 11.0.9 9.0.107, 10.1.43, 11.0.9
  18. Apache Tomcat Catalina is vulnerable to DoS attack through bypassing of size limits
    High · 7.5 CVE-2025-52520 >= 11.0.0-M1, < 11.0.9, >= 10.1.0-M1, < 10.1.43, >= 9.0.0.M1, < 9.0.107, >= 8.5.0, <= 8.5.100 11.0.9, 10.1.43, 9.0.107
  19. Apache Tomcat - DoS in multipart upload
    High · 7.5 CVE-2025-48988 >= 11.0.0-M1, < 11.0.8, >= 10.1.0-M1, < 10.1.42, >= 9.0.0.M1, < 9.0.106, >= 8.5.0, <= 8.5.100 11.0.8, 10.1.42, 9.0.106
  20. Apache Tomcat Denial of Service via invalid HTTP priority header this entry
    Medium CVE-2025-31650 >= 9.0.76, < 9.0.104, >= 10.1.10, < 10.1.40, >= 11.0.0-M2, < 11.0.6, >= 8.5.0, <= 8.5.100 9.0.104, 10.1.40, 11.0.6
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