CVE catalog
CVE-2026-69186
c-ares vulnerabilities
- Severity
- High · CVSS 8.6
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H - Published
- Source
- [NVD] · [CVE record]
- EPSS
- 0.47% · Oct 25, 2026
c-ares is an asynchronous resolver library. Prior to 1.34.7, ares_dns_parse() trusts the attacker-controlled ANCOUNT, NSCOUNT, and ARCOUNT fields before confirming that the DNS response contains enough bytes for the claimed records. Because process_answer() invokes parsing before transaction ID and question validation, a malicious DNS response can cause ares_dns_record_rr_prealloc() and ares_array_set_size() to reserve disproportionate heap memory for a tiny message. Repeated responses create large allocation and release cycles that can degrade or deny name resolution, without causing memory corruption or information disclosure. This issue is fixed in version 1.34.7.
Vulnerable and fixed packages
Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.
| Distribution | Package | Release | Version | Status |
|---|---|---|---|---|
| Debian | c-ares | sid | 1.34.9-1 | fixed |
| Debian | c-ares | forky | 1.34.8-1 | fixed |
| Debian | c-ares | trixie | 1.34.5-1+deb13u1 | vulnerable |
| Debian | c-ares | trixie-security | 1.34.5-1+deb13u1 | vulnerable |
| Debian | c-ares | bookworm | 1.18.1-3 | not affected |
| Ubuntu | c-ares | 24.04 | 1.19.1-3 | vulnerable |
| Ubuntu | c-ares | 24.04 | 1.20.1-1 | vulnerable |
| Ubuntu | c-ares | 24.04 | 1.26.0-1 | vulnerable |
| Ubuntu | c-ares | 24.04 | 1.27.0-1 | vulnerable |
| Ubuntu | c-ares | 24.04 | 1.27.0-1.0ubuntu1 | vulnerable |
| Ubuntu | c-ares | 24.04 | 1.27.0-1.0ubuntu1.1 | fixed |
| Ubuntu | c-ares | 26.04 | 1.34.5-1 | vulnerable |
| Ubuntu | c-ares | 26.04 | 1.34.6-1 | vulnerable |
| Ubuntu | c-ares | 26.04 | 1.34.6-1ubuntu0.1 | vulnerable |
| Ubuntu | c-ares | 26.04 | 1.34.6-1ubuntu0.2 | fixed |
| Ubuntu | c-ares | noble | 1.27.0-1.0ubuntu1.1 | fixed |
| Ubuntu | libc-ares-dev | noble | 1.27.0-1.0ubuntu1.1 | fixed |
| Ubuntu | libcares2 | noble | 1.27.0-1.0ubuntu1.1 | fixed |
Fixed-version evidence
| Distribution | Package | Type | Release | Fixed version | Urgency | Origin | Bugs |
|---|---|---|---|---|---|---|---|
| Debian | c-ares | source | sid | 1.34.7-1 | not yet assigned | Not reported | Not reported |
| Debian | c-ares | source | forky | 1.34.7-1 | not yet assigned | Not reported | Not reported |
| Debian | c-ares | source | trixie | (unfixed) | not yet assigned | Not reported | Not reported |
| Debian | c-ares | source | bookworm | Not affected | unimportant | Not reported | Not reported |
| Ubuntu | c-ares | deb | 24.04 | 1.27.0-1.0ubuntu1.1 | Not reported | UBUNTU-CVE-2026-69186 | Not reported |
| Ubuntu | c-ares | deb | 26.04 | 1.34.6-1ubuntu0.2 | Not reported | UBUNTU-CVE-2026-69186 | Not reported |
| Ubuntu | c-ares | deb | noble | 1.27.0-1.0ubuntu1.1 | Not reported | Not reported | Not reported |
| Ubuntu | libc-ares-dev | deb | noble | 1.27.0-1.0ubuntu1.1 | Not reported | Not reported | Not reported |
| Ubuntu | libcares2 | deb | noble | 1.27.0-1.0ubuntu1.1 | Not reported | Not reported | Not reported |
Notes
[trixie] c-ares: Minor issue
OpenFactory catalog packages
Matching against OpenFactory catalog package versions is in progress.
References
- [https://ftp.suse.com/pub/projects/security/csaf/opensuse-su-2026_11593-1.json]
- [https://nvd.nist.gov/vuln/detail/CVE-2026-69186]
- [https://osv.dev/vulnerability/DEBIAN-CVE-2026-69186]
- [https://osv.dev/vulnerability/UBUNTU-CVE-2026-69186]
- [https://security-tracker.debian.org/tracker/CVE-2026-69186]
- [https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-69186.json]
- [https://ubuntu.com/security/notices/USN-8951-1]
[Debian Security Tracker] · [FIRST EPSS] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX] · [SUSE security advisories and VEX] · [Ubuntu Security Notices (USN)]