CVE-2026-78383
Apache Tomcat: AJP denial of service via missing request body
Technology
Apache Tomcat
CVSS Score
7.5 / 10.0
Affected Versions
11.0.0-M1 to 11.0.25; 10.1.0-M1 to 10.1.59; 9.0.0.M1 to 9.0.121; end of life but known affected: 8.5.0 to 8.5.100, 7.0.0 to 7.0.109
Upstream Fix
11.0.26; 10.1.60; 9.0.122
Published
September 23, 2026
OSSeva Coverage
Fixed upstream
Description
An unauthenticated AJP request with no request body could pin an AJP processing thread, leading to denial of service. Only deployments with a reachable AJP connector are exposed. Made public on 23 September 2026 and rated Important by the Tomcat security team. Fixed in 11.0.26, 10.1.60 and 9.0.122.
Is your Apache Tomcat deployment affected?
If you're running 11.0.0-M1 to 11.0.25; 10.1.0-M1 to 10.1.59; 9.0.0.M1 to 9.0.121; end of life but known affected: 8.5.0 to 8.5.100, 7.0.0 to 7.0.109, you need this patch. Book a discovery call to get covered.
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Running Apache Tomcat 11.0.0-M1 to 11.0.25; 10.1.0-M1 to 10.1.59; 9.0.0.M1 to 9.0.121; end of life but known affected: 8.5.0 to 8.5.100, 7.0.0 to 7.0.109?
Send your work email and a senior engineer will tell you whether this CVE applies to your versions and who patches it. Reply within 1 business day.
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