CVE-2025-40775
Description
An assertion failure vulnerability was found in the BIND package. When an incoming DNS protocol message includes a Transaction Signature (TSIG), BIND always checks it. If the TSIG contains an invalid value in the algorithm field, BIND immediately aborts with an assertion failure. By sending specific messages to the server, an attacker can cause named to terminate unexpectedly, causing a denial of service.
Statement
No Red Hat products or offerings are affected by this vulnerability as the affected code is not used in Red Hat systems.
Although Red Hat does not ship this vulnerable code, we rated the impact of this vulnerability for the upstream community users marked as Important rather than a Moderate flaw because it triggers an assertion failure within BIND's core DNS handling logic, specifically in the TSIG validation path. Unlike typical input validation errors, which might allow an attacker to manipulate a single query's processing, this bug results in a complete and immediate crash of the named daemon. Since both authoritative servers and resolvers perform TSIG verification, the vulnerability can be exploited remotely by an unauthenticated attacker to cause repeated service outages, effectively disrupting DNS resolution for entire domains or networks.
Mitigation
Mitigation is either unavailable or does not meet Red Hat Product Security standards for usability, deployment, applicability, or stability.
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).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 7.5 | N/A | 7.5 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | None | N/A | None |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | None | N/A | None |
| Integrity Impact | None | N/A | None |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
cve.org: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Crash, Exit, or Restart
An attacker that can trigger an assert statement can still lead to a denial of service if the relevant code can be triggered by an attacker, and if the scope of the assert() extends beyond the attacker's own session.
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