SB20260409109 - Multiple vulnerabilities in Apache Tomcat (March 2026 release)

Description

This security bulletin contains information about 6 secuirty vulnerabilities.

1) Improper input validation (CVE-ID: CVE-2026-32990)

The vulnerability allows a remote attacker to bypass strict SNI checks.

The vulnerability exists due to improper input validation in SNI name and host name validation when processing TLS connections. A remote attacker can use differences in case between the SNI name and host name to bypass strict SNI checks.

2) Use of a broken or risky cryptographic algorithm (CVE-ID: CVE-2026-29146)

The vulnerability allows a remote attacker to decrypt protected communications.

The vulnerability exists due to the use of a padding-oracle-prone cryptographic mode in EncryptInterceptor when processing encrypted traffic with the default CBC configuration. A remote attacker can perform a padding oracle attack to decrypt protected communications.

3) Improper Certificate Validation (CVE-ID: CVE-2026-29145)

The vulnerability allows a remote user to bypass certificate revocation checks during authentication.

The vulnerability exists due to improper certificate validation in CLIENT_CERT authentication when processing OCSP checks in some scenarios with soft fail disabled. A remote user can present a certificate in affected scenarios to bypass certificate revocation checks during authentication.

Only some scenarios are affected when soft fail is disabled.

4) Configuration (CVE-ID: CVE-2026-29129)

The vulnerability allows a remote attacker to cause the server to use TLS cipher suites in an unintended order.

The vulnerability exists due to improper configuration handling in TLS 1.3 cipher suite configuration when negotiating TLS connections. A remote attacker can initiate a TLS connection to cause the server to use TLS cipher suites in an unintended order.

5) Open redirect (CVE-ID: CVE-2026-25854)

The vulnerability allows a remote attacker to redirect users to an arbitrary URI.

The vulnerability exists due to improper input validation in LoadBalancerDrainingValve when handling a specially crafted URL while a Tomcat node is in the disabled (draining) state. A remote attacker can send a specially crafted URL to redirect users to an arbitrary URI.

Only clustered deployments using LoadBalancerDrainingValve in the disabled (draining) state are affected.

6) Inconsistent interpretation of HTTP requests (CVE-ID: CVE-2026-24880)

The vulnerability allows a remote attacker to perform request smuggling.

The vulnerability exists due to improper input validation in HTTP/1.1 chunk extension handling when parsing chunked requests. A remote attacker can send a specially crafted request with an invalid chunk extension to perform request smuggling.

Exploitation requires a reverse proxy in front of Tomcat that allows CRLF sequences in an otherwise valid chunk extension.

Remediation

Install update from vendor's website.

References

• https://tomcat.apache.org/security-11.html#Fixed_in_Apache_Tomcat_11.0.20
• https://tomcat.apache.org/security-10.html#Fixed_in_Apache_Tomcat_10.1.53
• https://tomcat.apache.org/security-9.html#Fixed_in_Apache_Tomcat_9.0.116
• https://tomcat.apache.org/security-11.html#Fixed_in_Apache_Tomcat_11.0.20