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High

Improper Handling of Exceptional Conditions in Apache Tomcat

  • Disclosed: 13.08.2021
  • Updated: 11.10.2026 11:22

A vulnerability in Apache Tomcat allows an attacker to remotely trigger a denial of service. An error introduced as part of a change to improve error handling during non-blocking I/O meant that the error flag associated with the Request object was not reset between requests. This meant that once a non-blocking I/O error occurred, all future requests handled by that request object would fail. Users were able to trigger non-blocking I/O errors, e.g. by dropping a connection, thereby creating the possibility of triggering a DoS. Applications that do not use non-blocking I/O are not exposed to this vulnerability. This issue affects Apache Tomcat 10.0.3 to 10.0.4; 9.0.44; 8.5.64.

Affected software

Click a technology to see all vulnerabilities affecting it.

PlatformPackageVulnerable versionsFixed in
Java / Kotlin (Maven) org.apache.tomcat:tomcat >= 10.0.3, < 10.0.5, >= 9.0.0, < 9.0.45, < 8.5.65 10.0.5, 9.0.45, 8.5.65

References

CVSS score 7.5/10
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness (CWE)
CWE-755
Platform
Java / Kotlin (Maven)
Package
org.apache.tomcat:tomcat
Disclosed
13.08.2021
Updated
11.10.2026 11:22

Sources and licenses

OSV / GitHub Advisory Database - GHSA-44qp-qhfv-c7f6 - CC BY 4.0

Vulnerability history: org.apache.tomcat:tomcat

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 (162) in the archive
Total entries
162
First → latest
12.2018 08.2026
Without a fix
20
Exploited in attacks
1

Severity breakdown

  • Critical 8
  • High 40
  • Medium 102
  • Low 12

Disclosures per year

Severity:
  1. Improper Handling of Exceptional Conditions in Apache Tomcat this entry
    High · 7.5 CVE-2021-30639 >= 10.0.3, < 10.0.5, >= 9.0.0, < 9.0.45, < 8.5.65 10.0.5, 9.0.45, 8.5.65
  2. 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
  3. 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
  4. 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
  5. 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
  6. 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
  7. 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
  8. 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
  9. 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
  10. 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
  11. 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
  12. 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
  13. Apache Tomcat Missing Encryption of Sensitive Data vulnerability
    High · 7.5 Exploited in attacks CVE-2026-34486 >= 11.0.20, < 11.0.21, >= 10.1.53, < 10.1.54, >= 9.0.116, < 9.0.117 11.0.21, 10.1.54, 9.0.117
  14. Apache Tomcat: Padding Oracle vulnerability in EncryptInterceptor
    High · 7.5 CVE-2026-29146 >= 9.0.13, < 9.0.116, >= 10.1.50, < 10.1.53, >= 11.0.0-M1, < 11.0.20, >= 8.5.38, <= 8.5.100, >= 7.0.100, <= 7.0.109 9.0.116, 10.1.53, 11.0.20
  15. Apache Tomcat: CLIENT_CERT authentication does not fail as expected
    Critical · 9.1 CVE-2026-29145 >= 9.0.83, < 9.0.116, >= 10.1.0-M7, < 10.1.53, >= 11.0.0-M1, < 11.0.20 9.0.116, 10.1.53, 11.0.20
  16. 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
  17. 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
  18. Deserialization of Untrusted Data in Apache Tomcat
    High CVE-2013-2185 < 7.0.39 7.0.39
  19. Improper Neutralization of Input During Web Page Generation in Apache Tomcat
    High · 8.1 CVE-2015-5346 >= 9.0.0.M1, < 9.0.0.M2, >= 8.0.0.RC1, < 8.0.31, >= 7.0.0, < 7.0.66 9.0.0.M2, 8.0.31, 7.0.66
  20. Apache Tomcat allows remote attackers to bypass a CSRF protection mechanism by using a token
    High · 8.8 CVE-2015-5351 < 7.0.68, >= 8.0.0, < 8.0.31, >= 9.0.0.M0, < 9.0.0.M2 7.0.68, 8.0.31, 9.0.0.M2
  21. Apache Tomcat does not enforce the maxHttpHeaderSize limit
    High · 7.5 CVE-2011-0534 >= 6.0.0, < 6.0.32, >= 7.0.0, < 7.0.8 6.0.32, 7.0.8
Show more (20) Showing 21 of 48

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