CVE-2026-24733

Apache Tomcat: Security constraint bypass with HTTP/0.9

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

Apache Software Foundation · Apache Tomcat

CVSS v4.0 GitHub

2.7 LOWCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:U

CVSS v3.1 NVD

3.7 LOWCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N

CVSS v3.1 CNA

6.5 MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

EPSS

0.55% chance of exploitation in the next 30 days, 45th percentile

Published

2026-02-17

Updated

2026-03-11

Proof-of-concept exploits (1)

• Darabium/CVE-2026-247331★ · 2026-09-15

Security advisories

• https://lists.apache.org/thread/6xk3t65qpn1myp618krtfotbjn1qt90f
• advisories/GHSA-qq5r-98hh-rxc9

References

• CVE Record
• NVD entry

Related

• CVE-2017-12635
• CVE-2017-12636
• CVE-2024-28987
• CVE-2025-0401