CVE-2025-40777

Published: Jul 16, 2025Modified: Jun 17, 2026Deferred

7.5

Vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Exploitability: 3.9 / Impact: 3.6

Source: security-officer@isc.org (Secondary)

Description

If a `named` caching resolver is configured with `serve-stale-enable` `yes`, and with `stale-answer-client-timeout` set to `0` (the only allowable value other than `disabled`), and if the resolver, in the process of resolving a query, encounters a CNAME chain involving a specific combination of cached or authoritative records, the daemon will abort with an assertion failure. This issue affects BIND 9 versions 9.20.0 through 9.20.10, 9.21.0 through 9.21.9, and 9.20.9-S1 through 9.20.10-S1.

Related CWEs

CWE-617

Reachable Assertion

The product contains an assert() or similar statement that can be triggered by an attacker, which leads to an application exit or other behavior that is more severe than necessary.

References (2)

https://kb.isc.org/docs/cve-2025-40777

Source: security-officer@isc.org

http://www.openwall.com/lists/oss-security/2025/07/16/6

Source: af854a3a-2127-422b-91ae-364da2661108

Timeline

No history available yet.