CVE catalog
CVE-2026-33630
c-ares: CVE-2026-33630
- Severity
- High · CVSS 7.5
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Published
- Source
- [NVD] · [CVE record]
- EPSS
- 0.84% · Oct 25, 2026
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.
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 |
| Alpine | c-ares | 3.21 | 1.34.8-r0 | fixed |
| Alpine | c-ares | 3.22 | 1.34.8-r0 | fixed |
| Alpine | c-ares | 3.23 | 1.34.8-r0 | fixed |
| Alpine | c-ares | 3.24 | 1.34.8-r0 | 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 | fixed |
| Ubuntu | c-ares | 25.10 | 1.34.4-2.1 | vulnerable |
| Ubuntu | c-ares | 25.10 | 1.34.5-1 | vulnerable |
| Ubuntu | c-ares | 25.10 | 1.34.5-1ubuntu0.1 | vulnerable |
| 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 | fixed |
| Suse | c-ares | linux enterprise server 16.0 | 1.34.8-160000.1.1 | fixed |
| Suse | c-ares | linux enterprise server for sap applications 16.0 | 1.34.8-160000.1.1 | fixed |
| Suse | libcares2 | linux enterprise server 12 sp5-ltss | 1.9.1-9.24.1 | fixed |
| Suse | libcares2 | linux enterprise server ltss extended security 12 sp5 | 1.9.1-9.24.1 | fixed |
| Opensuse | c-ares | leap 16.0 | 1.34.8-160000.1.1 | fixed |
| Opensuse | c-ares | tumbleweed | 1.34.8-1.1 | 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 |
| Alpine | c-ares | apk | 3.21 | 1.34.8-r0 | Not reported | ALPINE-CVE-2026-33630 | Not reported |
| Alpine | c-ares | apk | 3.22 | 1.34.8-r0 | Not reported | ALPINE-CVE-2026-33630 | Not reported |
| Alpine | c-ares | apk | 3.23 | 1.34.8-r0 | Not reported | ALPINE-CVE-2026-33630 | Not reported |
| Alpine | c-ares | apk | 3.24 | 1.34.8-r0 | Not reported | ALPINE-CVE-2026-33630 | Not reported |
| Ubuntu | c-ares | deb | 26.04 | 1.34.6-1ubuntu0.1 | Not reported | USN-8844-1 | Not reported |
| Ubuntu | c-ares | deb | 26.04 | 1.34.6-1ubuntu0.1 | Not reported | UBUNTU-CVE-2026-33630 | Not reported |
| Suse | c-ares | rpm | linux enterprise server 16.0 | 1.34.8-160000.1.1 | Not reported | SUSE-SU-2026:23597-1 | Not reported |
| Suse | c-ares | rpm | linux enterprise server for sap applications 16.0 | 1.34.8-160000.1.1 | Not reported | SUSE-SU-2026:23597-1 | Not reported |
| Suse | libcares2 | rpm | linux enterprise server 12 sp5-ltss | 1.9.1-9.24.1 | Not reported | SUSE-SU-2026:3872-1 | Not reported |
| Suse | libcares2 | rpm | linux enterprise server ltss extended security 12 sp5 | 1.9.1-9.24.1 | Not reported | SUSE-SU-2026:3872-1 | Not reported |
| Opensuse | c-ares | rpm | leap 16.0 | 1.34.8-160000.1.1 | Not reported | OPENSUSE-SU-2026:21721-1 | Not reported |
| Opensuse | c-ares | rpm | tumbleweed | 1.34.8-1.1 | Not reported | OPENSUSE-SU-2026:11593-1 | Not reported |
Notes
[trixie] c-ares: Minor issue
OpenFactory catalog packages
[Debian 13 (Trixie)]
- [libc-ares2]Affected
Source package: [c-ares]
Details (4)
1.34.5-1+deb13u1· all · trixieAffected
dsa · c-ares · debian · 13
1.34.5-1+deb13u1· all · trixieAffected
dsa · c-ares · debian · 13
1.34.5-1+deb13u1· all · trixie-securityAffected
dsa · c-ares · debian · 13
1.34.5-1+deb13u1· all · trixie-securityAffected
dsa · c-ares · debian · 13
- [libcares2]Affected
Source package: [c-ares]
Details (4)
1.34.5-1+deb13u1· amd64 · trixieAffected
dsa · c-ares · debian · 13
1.34.5-1+deb13u1· arm64 · trixieAffected
dsa · c-ares · debian · 13
1.34.5-1+deb13u1· amd64 · trixie-securityAffected
dsa · c-ares · debian · 13
1.34.5-1+deb13u1· arm64 · trixie-securityAffected
dsa · c-ares · debian · 13
- [libc-ares-dev]Affected
Source package: [c-ares]
Details (4)
1.34.5-1+deb13u1· amd64 · trixieAffected
dsa · c-ares · debian · 13
1.34.5-1+deb13u1· arm64 · trixieAffected
dsa · c-ares · debian · 13
1.34.5-1+deb13u1· amd64 · trixie-securityAffected
dsa · c-ares · debian · 13
1.34.5-1+deb13u1· arm64 · trixie-securityAffected
dsa · c-ares · debian · 13
[openSUSE Tumbleweed]
- [c-ares-devel]Unknown
Source package: [c-ares]
Details (1)
1.34.8-1.1· x86_64 · tumbleweedUnknown · Fixed:
1.34.8-1.1Version impact unknown
dsa · c-ares · opensuse · tumbleweed
- [c-ares-utils]Unknown
Source package: [c-ares]
Details (1)
1.34.8-1.1· x86_64 · tumbleweedUnknown · Fixed:
1.34.8-1.1Version impact unknown
dsa · c-ares · opensuse · tumbleweed
- [libcares2]Unknown
Source package: [c-ares]
Details (1)
1.34.8-1.1· x86_64 · tumbleweedUnknown · Fixed:
1.34.8-1.1Version impact unknown
dsa · c-ares · opensuse · tumbleweed
- [libcares2-32bit]Unknown
Source package: [c-ares]
Details (1)
1.34.8-1.1· x86_64 · tumbleweedUnknown · Fixed:
1.34.8-1.1Version impact unknown
dsa · c-ares · opensuse · tumbleweed
[Debian 12 (Bookworm)]
- [libc-ares2]Not affected
Source package: [c-ares]
Details (2)
1.18.1-3· amd64 · bookwormNot affected
dsa · c-ares · debian · bookworm
1.18.1-3· arm64 · bookwormNot affected
dsa · c-ares · debian · bookworm
- [libc-ares-dev]Not affected
Source package: [c-ares]
Details (2)
1.18.1-3· amd64 · bookwormNot affected
dsa · c-ares · debian · bookworm
1.18.1-3· arm64 · bookwormNot affected
dsa · c-ares · debian · bookworm
Observed:
References
- [https://ftp.suse.com/pub/projects/security/csaf/rhsa-2026_42096.json]
- [https://nvd.nist.gov/vuln/detail/CVE-2026-33630]
- [https://osv.dev/vulnerability/ALPINE-CVE-2026-33630]
- [https://osv.dev/vulnerability/DEBIAN-CVE-2026-33630]
- [https://osv.dev/vulnerability/SUSE-SU-2026:23597-1]
- [https://osv.dev/vulnerability/SUSE-SU-2026:3872-1]
- [https://osv.dev/vulnerability/UBUNTU-CVE-2026-33630]
- [https://osv.dev/vulnerability/USN-8844-1]
- [https://osv.dev/vulnerability/openSUSE-SU-2026:11593-1]
- [https://osv.dev/vulnerability/openSUSE-SU-2026:21721-1]
- [https://security-tracker.debian.org/tracker/CVE-2026-33630]
- [https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-33630.json]
- [https://wid.cert-bund.de/.well-known/csaf/white/2026/wid-sec-w-2026-2419.json]
[CERT-Bund public advisories] · [Debian Security Tracker] · [FIRST EPSS] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX] · [SUSE security advisories and VEX]