CVE-2026-33630
Description
c-ares is an asynchronous resolver library. From ver 1.32.3 until 1.34.7, a use-after-free / double-free in c-ares' query-completion handling. The same flaw — a query's callback being invoked while the query is still linked in the channel's internal lookup structures — is present at multiple points in the resend/finish path (timeout handling, response handling, and query dispatch). If the query, or for ares_getaddrinfo() the owning host_query, is freed as a side effect of that callback, it is then accessed and/or freed a second time. This vulnerability is fixed in ver 1.34.7.
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
No mitigations published for this CVE yet.
The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.
Propose a mitigation on Community Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here withsource_tier=community-verified.
OS impact
SUSE Affected 1 release
| Version | Status | Fixed in |
|---|---|---|
| — | Affected | — |
Debian Mixed 5 releases
| Version | Status | Fixed in |
|---|---|---|
| trixie | Affected | — |
| sid | Fixed | 1.34.7-1 |
| forky | Fixed | 1.34.7-1 |
| bullseye | Fixed | 0 |
| bookworm | Fixed | 0 |
Alpine Fixed 4 releases
| Version | Status | Fixed in |
|---|---|---|
| v3.24 | Fixed | 1.34.8-r0 |
| v3.23 | Fixed | 1.34.8-r0 |
| v3.22 | Fixed | 1.34.8-r0 |
| v3.21 | Fixed | 1.34.8-r0 |
References
- https://security-tracker.debian.org/tracker/CVE-2026-33630
- https://www.suse.com/security/cve/CVE-2026-33630.html
- https://security.alpinelinux.org/vuln/CVE-2026-33630
- https://pkgs.alpinelinux.org/packages?name=c-ares
- https://github.com/c-ares/c-ares/commit/d823199b688052dcdc1646f2ab4cb8c16b1c644a
- https://github.com/c-ares/c-ares/releases/tag/v1.34.7
- https://github.com/c-ares/c-ares/security/advisories/GHSA-6wfj-rwm7-3542
CWEs
CWE-415 CWE-416
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.