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Critical

Apache Tomcat - HTTP/2 request headers not validated

  • Disclosed: 12.05.2026
  • Updated: 11.10.2026 13:20

Versions Affected: Apache Tomcat 11.0.0-M1 to 11.0.21 Apache Tomcat 10.1.0-M1 to 10.1.54 Apache Tomcat 9.0.0.M1 to 9.0.117 Older, unsupported versions may also be affected

Description: HTTP/2 request headers were not validated which may have triggered unexpected application behaviour if the application (quite reasonably) assumed that header value exposed through the Servlet API would be specification compliant.

Mitigation: Users of the affected versions should apply one of the following mitigations:

  • Upgrade to Apache Tomcat 11.0.22 or later
  • Upgrade to Apache Tomcat 10.1.55 or later
  • Upgrade to Apache Tomcat 9.0.118 or later

Credit: This issue was identified by Dawit Jeong (@dawitngoliath)

Affected software

Click a technology to see all vulnerabilities affecting it.

PlatformPackageVulnerable versionsFixed in
Java / Kotlin (Maven) org.apache.tomcat.embed:tomcat-embed-core >= 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
Java / Kotlin (Maven) org.apache.tomcat:tomcat >= 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
Java / Kotlin (Maven) org.apache.tomcat:tomcat-coyote >= 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

References

CVSS score 9.8/10
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness (CWE)
CWE-20
Platform
Java / Kotlin (Maven)
Package
org.apache.tomcat.embed:tomcat-embed-core, org.apache.tomcat:tomcat, org.apache.tomcat:tomcat-coyote
Disclosed
12.05.2026
Updated
11.10.2026 13:20

Sources and licenses

OSV / GitHub Advisory Database - GHSA-r29c-68gh-xp6x - 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 this entry
    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: Potential RCE and/or information disclosure and/or information corruption with partial PUT
    Critical · 9.8 Exploited in attacks CVE-2025-24813 >= 11.0.0-M1, < 11.0.3, >= 10.1.0-M1, < 10.1.35, >= 9.0.0.M1, < 9.0.99, >= 8.5.0, <= 8.5.100 11.0.3, 10.1.35, 9.0.99
Show more (20) Showing 20 of 47

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