SB2026051281 - Multiple vulnerabilities in Apache Tomcat

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Main Vulnerability Database SB2026051281

SB2026051281 - Multiple vulnerabilities in Apache Tomcat

Published: May 12, 2026 Updated: June 23, 2026

Security Bulletin ID SB2026051281
CSH Severity
Medium
Patch available
YES
Number of vulnerabilities 7
Exploitation vector Remote access
Highest impact Data manipulation

Breakdown by Severity

Medium 71% Low 29%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 7 vulnerabilities.


1) Improper access control (CVE-ID: CVE-2026-43515)

CWE-ID: CWE-284 - Improper Access Control

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:P/U:Green


The vulnerability allows a remote attacker to bypass security constraints.

The vulnerability exists due to improper access control in HTTP method constraint processing when evaluating multiple security constraints for the same extension pattern. A remote attacker can send a request using an improperly constrained HTTP method to bypass security constraints.


2) Information Exposure Through Timing Discrepancy (CVE-ID: CVE-2026-43514)

CWE-ID: CWE-208 - Information Exposure Through Timing Discrepancy

CVSSv4: CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear


The vulnerability allows a remote attacker to disclose the AJP secret.

The vulnerability exists due to observable timing discrepancy in AJP secret comparison when validating the AJP secret. A remote attacker can perform a timing attack to disclose the AJP secret.

Exploitation is limited to an attacker on the local network.


3) Improper Handling of Case Sensitivity (CVE-ID: CVE-2026-43513)

CWE-ID: CWE-178 - Improper Handling of Case Sensitivity

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Green


The vulnerability allows a remote attacker to weaken brute-force protection against a user's password.

The vulnerability exists due to improper input handling in LockOutRealm when processing case-insensitive user names. A remote attacker can vary the case of a user name during authentication attempts to weaken brute-force protection against a user's password.

This affects Realms where user names are treated as case insensitive.


4) Improper Authentication (CVE-ID: CVE-2026-43512)

CWE-ID: CWE-287 - Improper Authentication

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:P/U:Green


The vulnerability allows a remote attacker to authenticate as an unknown user.

The vulnerability exists due to improper authentication in the DIGEST authenticator when processing authentication for users not known to the configured Realm. A remote attacker can submit the password "null" for an unknown user to authenticate as an unknown user.

This occurs only when DIGEST authentication is configured.


5) Information disclosure (CVE-ID: CVE-2026-42498)

CWE-ID: CWE-200 - Exposure of sensitive information to an unauthorized actor

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear


The vulnerability allows a remote user to disclose authentication headers to a redirect target host.

The vulnerability exists due to exposure of sensitive information in Tomcat's WebSocket client when following a redirected WebSocket request after authentication. A remote user can trigger a redirect after authentication to disclose authentication headers to a redirect target host.

The issue occurs only if a WebSocket request is redirected after authentication.


6) Input validation error (CVE-ID: CVE-2026-41293)

CWE-ID: CWE-20 - Improper input validation

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Green


The vulnerability allows a remote attacker to trigger unexpected application behavior.

The vulnerability exists due to improper input validation in HTTP/2 request header handling when exposing header values through the Servlet API. A remote attacker can send crafted HTTP/2 request headers to trigger unexpected application behavior.

This may affect applications that assume header values exposed through the Servlet API are specification compliant.


7) Resource exhaustion (CVE-ID: CVE-2026-41284)

CWE-ID: CWE-400 - Resource exhaustion

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U/U:Green


The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to uncontrolled resource consumption in WebDAV LOCK and PROPFIND handling when processing request bodies. A remote attacker can send a large request body to cause a denial of service.

The affected requests are available to unauthenticated users.


Remediation

Install update from vendor's website.

References