Reachable assertion in ISC BIND - CVE-2026-97313
Published: October 21, 2026
Vulnerability identifier: #VU156715
CSH Severity: Medium
CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-97313
CWE-ID: CWE-617
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to cause a denial of service by triggering an unexpected exit of a BIND server.
The vulnerability exists due to a reachable assertion in BIND's response policy zone (RPZ) query handling when processing a recursive query followed by a non-recursive query. A remote attacker can send a query with recursion desired (RD=1) followed by a query with recursion disabled (RD=0) to trigger an assertion failure and terminate the server.
The server must allow recursive queries and have at least two RPZ zones configured: one with the default setting of "recursive-only yes" and another with "recursive-only no".
Affected software
ISC BIND
How to mitigate CVE-2026-97313
Install security update from vendor's website.
ISC BIND - addressed in versions 9.20.30, 9.20.30-s1, 9.21.27