CVE-2026-65905
Description
A flaw was found in Apache Tomcat. This vulnerability, an authentication bypass by capture-replay, affects the DIGEST authenticator. A remote attacker can exploit this by making a specially crafted DIGEST authenticated request with a nonceCount at the upper boundary of the replay window. This allows the attacker to replay the request once, potentially bypassing authentication.
Statement
This Moderate impact flaw in Apache Tomcat's DIGEST authenticator allows a limited authentication bypass through a replay attack. While the attack complexity is high, a remote attacker could potentially replay a single authenticated request if the nonceCount is at the upper boundary of the replay window, leading to limited unauthorized access. This vulnerability affects configurations utilizing DIGEST authentication.
Mitigation
To mitigate this issue, disable DIGEST authentication in Apache Tomcat if it is not a required authentication mechanism for your deployment. Refer to the Apache Tomcat documentation for guidance on configuring authentication methods. Disabling DIGEST authentication will affect services that depend on it. A restart of the Tomcat service is necessary for the configuration changes to be applied.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 4.8 | N/A | 9.8 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | High | N/A | Low |
| Privileges Required | None | N/A | None |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | Low | N/A | High |
| Integrity Impact | Low | N/A | High |
| Availability Impact | None | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N
cve.org: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Understanding the Weakness (CWE)
Access Control
Technical Impact: Gain Privileges or Assume Identity
Messages sent with a capture-relay attack allow access to resources which are not otherwise accessible without proper authentication.
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