UBUNTU-CVE-2026-33630

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Source
https://ubuntu.com/security/CVE-2026-33630
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33630.json
JSON Data
https://api.osv.dev/v1/vulns/UBUNTU-CVE-2026-33630
Upstream
Downstream
Related
Published
2026-09-03T19:17:00Z
Modified
2026-09-29T23:41:46Z
Severity
  • 7.5 (High) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H CVSS Calculator
  • Ubuntu - medium
Summary
[none]
Details

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.

References

Affected packages

Ubuntu:25.10 / c-ares

Package

Name
c-ares
Purl
pkg:deb/ubuntu/c-ares?arch=source&distro=questing

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected

Affected versions

1.*
1.34.4-2.1
1.34.5-1
1.34.5-1ubuntu0.1

Ecosystem specific 

{
    "binaries":  [
        {
            "binary_name":  "libc-ares2",
            "binary_version":  "1.34.5-1ubuntu0.1"
        },
        {
            "binary_name":  "libcares2",
            "binary_version":  "1.34.5-1ubuntu0.1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33630.json"

Ubuntu:26.04:LTS / c-ares

Package

Name
c-ares
Purl
pkg:deb/ubuntu/c-ares?arch=source&distro=resolute

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected
Fixed
1.34.6-1ubuntu0.1

Affected versions

1.*
1.34.5-1
1.34.6-1

Ecosystem specific 

{
    "availability":  "No subscription required",
    "binaries":  [
        {
            "binary_name":  "libc-ares2",
            "binary_version":  "1.34.6-1ubuntu0.1"
        },
        {
            "binary_name":  "libcares2",
            "binary_version":  "1.34.6-1ubuntu0.1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33630.json"