Reachable Assertion Affecting bind package, versions [,9.20.10)[9.21.0,9.21.9)
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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- published21 Jul 2025
- disclosed16 Jul 2025
- creditUnknown
Introduced: 16 Jul 2025
NewCVE-2025-40777 (opens in a new tab)How to fix?
Upgrade bind to version 9.20.10, 9.21.9 or higher.
Overview
Affected versions of this package are vulnerable to Reachable Assertion in the stale-answer-client-timeout process. An attacker can cause the daemon to abort by sending queries that trigger a specific CNAME chain involving a particular combination of cached or authoritative records. This is only exploitable if serve-stale-enable is set to yes and stale-answer-client-timeout is set to 0.
Workaround
This vulnerability can be mitigated by setting either stale-answer-client-timeout off; or stale-answer-enable no; in the configuration file.