Bug 2558426

Summary:	CVE-2026-97313 dhcp: bind: Denial of service via assertion failure in RPZ query processing [fedora-all]
Product:	[Fedora] Fedora	Reporter:	Marco Benatto <mbenatto>
Component:	dhcp	Assignee:	Martin Osvald 🛹 <mosvald>
Status:	CLOSED NOTABUG	QA Contact:	Fedora Extras Quality Assurance <extras-qa>
Severity:	high	Docs Contact:
Priority:	high
Version:	rawhide	CC:	fhrdina, jorton, mosvald, pavel, pemensik
Target Milestone:	---	Keywords:	Security, SecurityTracking
Target Release:	---
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:	{"flaws": ["d662a4c9-d5ae-498e-8c95-9b4e152ab530"]}
Fixed In Version:		Doc Type:	---
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2026-10-22 07:41:27 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:
Bug Blocks:	2556415

Description Marco Benatto 2026-10-21 18:00:58 UTC

Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.

A recursive BIND server that receives a query with recursion desired (RD=1) followed by a non-recursive query (RD=0) may exit with an assertion failure, resulting in a denial of service. To be vulnerable, the BIND server must allow recursive queries and have at least two RPZ zones configured: one with the default setting of "recursive-only yes", and the other with "recursive-only no".

Comment 1 Martin Osvald 🛹 2026-10-22 07:41:27 UTC

ISC DHCP is not affected.

CVE-2026-97313 is a denial of service in the BIND name server (named): an assertion failure in
the query processing code when a recursive server with two Response Policy Zones (one with
"recursive-only yes" and one with "recursive-only no") receives a query with RD=1 followed by a
query with RD=0. The affected logic is in named's server-side query handling and client-object
reuse, which is not part of the libraries bundled in ISC DHCP.

ISC DHCP bundles only parts of the BIND 9.11.14 libraries (libisc, libdns, libisccfg, libirs).
It uses them for DDNS (TSIG, DNS message construction and parsing, DHCID), OMAPI, and basic
functions (configuration handling, data structures, logging, networking primitives). DHCP does
not implement a DNS server, does not use Response Policy Zones (no code in client, common,
server, relay, omapip or dhcpctl references RPZ or response-policy; the DNS client paths in
libdns used by DDNS do not set up RPZ), and does not process recursive queries from clients.