CVE-2025-40777
published 2025-07-16CVE-2025-40777: 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…
high7.5CVSS 3.1
AVNACLPRNUINSUCNINAH
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.
Affected
9 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| debian | bind9 | < bind9 1:9.20.11-1 (forky) | bind9 1:9.20.11-1 (forky) |
| isc | bind | >= 0 < 9.20.11-r0 | 9.20.11-r0 |
| isc | bind | >= 0 < 9.20.11-r0 | 9.20.11-r0 |
| isc | bind9 | >= 0 < 1:9.20.11-1 | 1:9.20.11-1 |
| isc | bind9 | >= 0 < 1:9.20.11-1 | 1:9.20.11-1 |
| isc | bind_9 | 9.20.0 – 9.20.10 | — |
| isc | bind_9 | 9.20.9-S1 – 9.20.10-S1 | — |
| isc | bind_9 | 9.21.0 – 9.21.9 | — |
| msrc | azl3_bind_9.20.11-1_on_azure_linux_3.0 | — | — |
CVSS provenance
nvdv3.17.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
osv7.5HIGH