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CVE-2026-33630

c-ares : Use-after-free / double-free in c-ares query-completion handling, remotely triggerable via ares_getaddrinfo() over TCP

Published: Sep 3, 2026Updated: Sep 9, 2026 Sources: CVE List NVDCWE-415
7.5HIGH
NVD MITRE
EPSS Score
0.5%
Top 61.4%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
No Fix Available
Self-Check
OpenVAS

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.

No summary for this CVE yet.

CVSS Vector Breakdown

AV:NAC:LPR:NUI:NS:UC:NI:NA:H
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:NConfidentiality
None
I:NIntegrity
None
A:HAvailability
High
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Weaknesses

CWE-415CWE-416

Affected Products

c-ares
oss-project
c-aresLibrary
OSS Libraries / generic-library

Exploitability

No known exploits, KEV entries, or remediation guidance available for this vulnerability yet.
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Attack Graph

Products CVE Techniques Tactics

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MITRE ATT&CK

2 techniques
Initial Access
Privilege Escalation
View detailed technique mapping

References

https://github.com/c-ares/c-ares/commit/1fa3b86a0b8d18fe7b60f3228a01d770feb026bc
github.com
https://github.com/c-ares/c-ares/commit/d823199b688052dcdc1646f2ab4cb8c16b1c644a
github.com
https://github.com/c-ares/c-ares/pull/1237
github.com
and 2 more references View all →
News mentions
1

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