CVE-2026-86248 Apache Tomcat - Authentication Bypass

Apache Tomcat 11.0.0-M14 through 11.0.25, 10.1.22 through 10.1.59, and 9.0.92 through 9.0.121 contain an authentication bypass caused by CLIENT_CERT authentication not failing as expected when soft fail is disabled, letting attackers bypass authentication, exploit requires specific CLIENT_CERT soft fail configuration.

CVSS base score 9.8 /10
Critical
CISA KEV
Not listed
Public exploit
None known
EPSS
0.39% chance of exploitation in 30 days
View the NVD record ↗

Details

Type
Authentication Bypass
Impact
Broken Authentication
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Published
23 September 2026
Updated
15 October 2026
Weakness
CWE-287

Vendor fix

Upgrade to versions 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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