CVE-2026-69184

Name	CVE-2026-69184
Description	c-ares is an asynchronous resolver library. Prior to 1.34.7, ares_dns_name_parse() enforces backward DNS compression pointers but does not bound the total pointer hops or assembled name length. A malicious DNS server can send a response containing a long descending pointer chain and many resource records whose NAME or RDATA fields refer to the chain, causing repeated decompression work that grows quadratically with message size. A single crafted response can stall the single-threaded c-ares event loop and deny DNS resolution, without causing memory corruption or information disclosure. This issue is fixed in version 1.34.7.
Source	CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
c-ares (PTS)	bookworm	1.18.1-3	fixed
	trixie (security), trixie	1.34.5-1+deb13u1	vulnerable
	forky, sid	1.34.8-1	fixed

The information below is based on the following data on fixed versions.

Package	Type	Release	Fixed Version
c-ares	source	bullseye	(not affected)
c-ares	source	bookworm	(not affected)
c-ares	source	(unstable)	1.34.7-1

Notes

[trixie] - c-ares <no-dsa> (Minor issue)
[bookworm] - c-ares <not-affected> (Vulnerable 1.34 DNS-name decompression parser (src/lib/record/ares_dns_name.c, ares_buf) not present)
[bullseye] - c-ares <not-affected> (Vulnerable 1.34 DNS-name decompression parser not present)
https://www.openwall.com/lists/oss-security/2026/07/06/8
https://github.com/c-ares/c-ares/security/advisories/GHSA-pjmc-gx33-gc76
Fixed by: https://github.com/c-ares/c-ares/commit/f1288bbc70e9a1e0a77134c2382157e52d326aea (main)
Fixed by: https://github.com/c-ares/c-ares/commit/5c8341ba6ff3a8e4e4dfd616f8ed0418838b8b7b (v1.34.7)