CVE-2026-78383 Apache Tomcat - Denial of Service

Apache Tomcat 11.0.0-M1 through 11.0.25, 10.1.0-M1 through 10.1.59, and 9.0.0.M1 through 9.0.121 contain a denial of service caused by allocation of resources without limits in AJP processing threads, letting unauthenticated attackers pin threads and exhaust resources, exploit requires unauthenticated AJP request.

CVSS base score 7.5 /10
High
CISA KEV
Not listed
Public exploit
None known
Authentication
Not required
EPSS
0.38% chance of exploitation in 30 days
View the NVD record ↗

Details

Type
Denial of Service
Impact
Denial Of Service
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Published
23 September 2026
Updated
15 October 2026
Weakness
CWE-770

Vendor fix

Upgrade to versions 11.0.26, 10.1.60, or 9.0.122 or later.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

References

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