CVE-2026-86247 Apache Tomcat Native - Authentication Bypass

Apache Tomcat Native 2.0.0 through 2.0.15 and 1.3.0 through 1.3.8 contain a race condition caused by thread handling in client certificate verification, letting attackers downgrade verification requirements, exploit requires specific configuration.

CVSS base score 7.4 /10
High
CISA KEV
Not listed
Public exploit
None known
EPSS
0.22% 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:H/PR:N/UI:N/S:U/C:H/I:H/A:N
Published
23 September 2026
Updated
15 October 2026
Weakness
CWE-366

Vendor fix

Upgrade to version 2.0.16 or 1.3.9 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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