CVE-2025-40777

HIGH EPSS 54.5%

Published Jul 16, 202511mo ago · Modified Jun 17, 20262w ago

7.5 CVSS 3.1

High

Published Jul 16, 2025 11mo ago

Last Modified Jun 17, 2026 2w ago

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.

CVSS Details

Base Score

7.5

Exploitability

3.9

Impact

3.6

Vector string

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

Attack Vector Network

Attack Complexity Low

Privileges Required None

User Interaction None

Scope Unchanged

Confidentiality None

Integrity None

Availability High

Threat Intelligence

EPSS Exploit Probability

54.5% percentile

Exploit & Patch Status

No Known Exploit

No Patch Available

Weaknesses 1

CWE-617

References 2

openwall.com http://www.openwall.com/lists/oss-security/2025/07/16/6
kb.isc.org https://kb.isc.org/docs/cve-2025-40777

Remediation

No remediation data recorded yet

Check vendor advisories and the NVD entry for patch availability.