Reversible One-Way Hash in ISC BIND - CVE-2025-40776
Published: July 17, 2025
Vulnerability identifier: #VU113025
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N/E:U/U:Green
CVE-ID: CVE-2025-40776
CWE-ID: CWE-328
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: ISC
Affected software:
ISC BIND
ISC BIND
Detailed vulnerability description
The vulnerability allows a remote attacker to perform cache poisoning attacks.
The vulnerability exists due to named caching resolver is configured to send ECS (EDNS Client Subnet) options. In such configuration the resolver can be compelled to make queries that slightly increase the odds of guessing the source port and other details necessary to bypass the original birthday cache poisoning attack mitigations.A remote attacker can poison DNS cache.
How to mitigate CVE-2025-40776
Install updates from vendor's website.