CVE-2026-24733: Apache Tomcat: Security constraint bypass with HTTP/0.9

Published Feb 17, 2026
·
Updated

Improper Input Validation vulnerability in Apache Tomcat.

Tomcat did not limit HTTP/0.9 requests to the GET method. If a security constraint was configured to allow HEAD requests to a URI but deny GET requests, the user could bypass that constraint on GET requests by sending a (specification invalid) HEAD request using HTTP/0.9.

This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.14, from 10.1.0-M1 through 10.1.49, from 9.0.0.M1 through 9.0.112.

Older, EOL versions are also affected.

Users are recommended to upgrade to version 11.0.15 or later, 10.1.50 or later or 9.0.113 or later, which fixes the issue.

Affected Software

77 affected componentsFixes available
Apache Tomcat>=11.0.0-M1<=11.0.14, >=10.1.0-M1<=10.1.49, >=9.0.0.M1<=9.0.112
maven/org.apache.tomcat:tomcat-catalina<9.0.112
9.0.112
maven/org.apache.tomcat:tomcat-catalina>=10.1.0-M1<10.1.49
10.1.49
maven/org.apache.tomcat:tomcat-catalina>=11.0.0-M1<11.0.14
11.0.14
maven/org.apache.tomcat:tomcat<9.0.112
9.0.112
maven/org.apache.tomcat:tomcat>=10.1.0-M1<10.1.49
10.1.49
maven/org.apache.tomcat:tomcat>=11.0.0-M1<11.0.14
11.0.14
maven/org.apache.tomcat.embed:tomcat-embed-core<9.0.112
9.0.112
maven/org.apache.tomcat.embed:tomcat-embed-core>=10.1.0-M1<10.1.49
10.1.49
maven/org.apache.tomcat.embed:tomcat-embed-core>=11.0.0-M1<11.0.14
11.0.14
Apache Tomcat>=9.0.1<9.0.113
Apache Tomcat>=10.1.1<10.1.50
Apache Tomcat>=11.0.1<11.0.15
Apache Tomcat=9.0.0-milestone1
Apache Tomcat=9.0.0-milestone10
Apache Tomcat=9.0.0-milestone11
Apache Tomcat=9.0.0-milestone12
Apache Tomcat=9.0.0-milestone13
Apache Tomcat=9.0.0-milestone14
Apache Tomcat=9.0.0-milestone15
Apache Tomcat=9.0.0-milestone16
Apache Tomcat=9.0.0-milestone17
Apache Tomcat=9.0.0-milestone18
Apache Tomcat=9.0.0-milestone19
Apache Tomcat=9.0.0-milestone2
Apache Tomcat=9.0.0-milestone20
Apache Tomcat=9.0.0-milestone21
Apache Tomcat=9.0.0-milestone22
Apache Tomcat=9.0.0-milestone23
Apache Tomcat=9.0.0-milestone24
Apache Tomcat=9.0.0-milestone25
Apache Tomcat=9.0.0-milestone26
Apache Tomcat=9.0.0-milestone27
Apache Tomcat=9.0.0-milestone3
Apache Tomcat=9.0.0-milestone4
Apache Tomcat=9.0.0-milestone5
Apache Tomcat=9.0.0-milestone6
Apache Tomcat=9.0.0-milestone7
Apache Tomcat=9.0.0-milestone8
Apache Tomcat=9.0.0-milestone9
Apache Tomcat=10.0.0-milestone1
Apache Tomcat=10.0.0-milestone10
Apache Tomcat=10.0.0-milestone2
Apache Tomcat=10.0.0-milestone3
Apache Tomcat=10.0.0-milestone4
Apache Tomcat=10.0.0-milestone5
Apache Tomcat=10.0.0-milestone6
Apache Tomcat=10.0.0-milestone7
Apache Tomcat=10.0.0-milestone8
Apache Tomcat=10.0.0-milestone9
Apache Tomcat=11.0.0-milestone1
Apache Tomcat=11.0.0-milestone10
Apache Tomcat=11.0.0-milestone11
Apache Tomcat=11.0.0-milestone12
Apache Tomcat=11.0.0-milestone13
Apache Tomcat=11.0.0-milestone14
Apache Tomcat=11.0.0-milestone15
Apache Tomcat=11.0.0-milestone16
Apache Tomcat=11.0.0-milestone17
Apache Tomcat=11.0.0-milestone18
Apache Tomcat=11.0.0-milestone19
Apache Tomcat=11.0.0-milestone2
Apache Tomcat=11.0.0-milestone20
Apache Tomcat=11.0.0-milestone21
Apache Tomcat=11.0.0-milestone22
Apache Tomcat=11.0.0-milestone23
Apache Tomcat=11.0.0-milestone24
Apache Tomcat=11.0.0-milestone25
Apache Tomcat=11.0.0-milestone26
Apache Tomcat=11.0.0-milestone3
Apache Tomcat=11.0.0-milestone4
Apache Tomcat=11.0.0-milestone5
Apache Tomcat=11.0.0-milestone6
Apache Tomcat=11.0.0-milestone7
Apache Tomcat=11.0.0-milestone8
Apache Tomcat=11.0.0-milestone9
IBM API Connect V12 OnPrem<=All

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade maven/org.apache.tomcat:tomcat-catalina to a version that resolves this vulnerability.

    Fixed in 9.0.112
  2. Upgrade

    Upgrade maven/org.apache.tomcat:tomcat-catalina to a version that resolves this vulnerability.

    Fixed in 10.1.49
  3. Upgrade

    Upgrade maven/org.apache.tomcat:tomcat-catalina to a version that resolves this vulnerability.

    Fixed in 11.0.14
  4. Upgrade

    Upgrade maven/org.apache.tomcat:tomcat to a version that resolves this vulnerability.

    Fixed in 9.0.112
  5. Upgrade

    Upgrade maven/org.apache.tomcat:tomcat to a version that resolves this vulnerability.

    Fixed in 10.1.49
  6. Upgrade

    Upgrade maven/org.apache.tomcat:tomcat to a version that resolves this vulnerability.

    Fixed in 11.0.14
  7. Upgrade

    Upgrade maven/org.apache.tomcat.embed:tomcat-embed-core to a version that resolves this vulnerability.

    Fixed in 9.0.112
  8. Upgrade

    Upgrade maven/org.apache.tomcat.embed:tomcat-embed-core to a version that resolves this vulnerability.

    Fixed in 10.1.49
  9. Upgrade

    Upgrade maven/org.apache.tomcat.embed:tomcat-embed-core to a version that resolves this vulnerability.

    Fixed in 11.0.14
  10. Upgrade

    Upgrade Apache Tomcat to a version that resolves this vulnerability.

    Fixed in 11.0.15 or later
  11. Upgrade

    Upgrade Apache Tomcat to a version that resolves this vulnerability.

    Fixed in 10.1.50 or later
  12. Upgrade

    Upgrade Apache Tomcat to a version that resolves this vulnerability.

    Fixed in 9.0.113 or later

Event History

Feb 17, 2026
CVE Published
via MITRE·06:50 PM
Data Sourced
via MITRE·06:50 PM
DescriptionWeakness
Data Sourced
via NVD·07:21 PM
DescriptionWeakness
Data Sourced
via NVD·07:21 PM
SeverityAffected Software
Data Sourced
via Red Hat·08:05 PM
DescriptionSeverityAffected Software
Advisory Published
via GitHub·09:31 PM
Data Sourced
via GitHub·09:31 PM
DescriptionWeaknessAffected Software
Jul 7, 2026
Data Sourced
via IBM·12:00 AM
DescriptionAffected Software

Parent advisories

This vulnerability appears in the following advisories.

Free Weekly Intel

Don't miss critical vulnerabilities

Join thousands of security professionals who receive our weekly digest of trending CVEs, zero-days, and exploited vulnerabilities.

No spam. Unsubscribe anytime.

Frequently Asked Questions

1

What is the severity of CVE-2026-24733?

CVE-2026-24733 is classified as a medium severity vulnerability due to its potential to bypass security constraints in Apache Tomcat.

2

How do I fix CVE-2026-24733?

To fix CVE-2026-24733, upgrade Apache Tomcat to version 9.0.112, 10.1.49, or 11.0.14.

3

What versions of Apache Tomcat are affected by CVE-2026-24733?

CVE-2026-24733 affects Apache Tomcat versions 9.0.0-M1 to 9.0.112, 10.1.0-M1 to 10.1.49, and 11.0.0-M1 to 11.0.14.

4

What type of attack can exploit CVE-2026-24733?

CVE-2026-24733 can be exploited by sending HTTP/0.9 requests that bypass security constraints, allowing unauthorized access to secured resources.

5

Is CVE-2026-24733 specific to any configuration settings?

Yes, CVE-2026-24733 specifically impacts configurations that allow HEAD requests while denying GET requests, enabling a bypass.

Company

Resources

Contact

SecAlerts Pty Ltd.
132 Wickham Terrace
Fortitude Valley,
QLD 4006, Australia
info@secalerts.co
By using SecAlerts services, you agree to our services end-user license agreement. This website is safeguarded by reCAPTCHA and governed by the Google Privacy Policy and Terms of Service. All names, logos, and brands of products are owned by their respective owners, and any usage of these names, logos, and brands for identification purposes only does not imply endorsement. If you possess any content that requires removal, please get in touch with us.
© 2026 SecAlerts Pty Ltd.
ABN: 70 645 966 203, ACN: 645 966 203
CVE-2026-24733 - Apache Tomcat: Security constraint bypass with HTTP/0.9 - SecAlerts