CVE-2026-78437 Apache Tomcat - Denial of Service

Apache Tomcat 11.0.19 through 11.0.25, 10.1.53 through 10.1.59, and 9.0.116 through 9.0.121 contain an incomplete cleanup vulnerability caused by malformed requests, letting attackers cause requests from other users to fail, exploit requires timing conditions.

CVSS base score 7.3 /10
High
CISA KEV
Not listed
Public exploit
None known
EPSS
0.26% 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:L/I:L/A:L
Published
23 September 2026
Updated
15 October 2026
Weakness
CWE-459

Vendor fix

Upgrade to version 11.0.26, 10.1.60, or 9.0.122.

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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