CVE-2025-40777 | BDVDB-2026-286403 Detail
ISCBIND 9
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.
Impact#
If an attacker is able to make queries that yield the necessary combination of circumstances, they can force `named` to exit.
Weaknesses#
- CWE-617 Reachable Assertion
References#
Exploit#
No public exploit known
History#
- Version 1Record published in the CVE List.
- Version 2Most recent update recorded in the CVE List.