CVE-2026-86350 Apache Tomcat - HTTP Request Smuggling

Apache Tomcat 11.0.22 through 11.0.25, 10.1.55 through 10.1.59, and 9.0.118 through 9.0.121 contain an HTTP request smuggling caused by regression in fix for CVE-2026-41293, letting attackers trigger request header mix-up, exploit requires crafted HTTP/2 requests.

CVSS base score 9.1 /10
Critical
CISA KEV
Not listed
Public exploit
Proof of concept available
Authentication
Not required
EPSS
0.31% chance of exploitation in 30 days
View the NVD record ↗

Details

Type
HTTP Request Smuggling
Impact
HTTP Request Smuggling
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Published
23 September 2026
Updated
15 October 2026
Weakness
CWE-444

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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