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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

Quick assessment

Affected
c-ares c-ares
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

c-ares是c-ares组织开源的一个用于异步 DNS 请求的 C 库。 c-ares 1.32.3版本至1.34.7之前版本存在资源管理错误漏洞，该漏洞源于查询完成处理中的释放后重用和双重释放问题，可能导致释放后重用或双重释放。

CVSS 7.5 · High EPSS 0.84% · P58

Possible ATT&CK Techniques 1 AI

T1190 · Exploit Public-Facing Application

Affected Version Matrix 1

VendorProduct Version RangeStatus
c-ares c-ares >= 1.32.3, < 1.34.7 affected
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I. Basic Information for CVE-2026-33630

Vulnerability Information
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Vulnerability Title
c-ares : Use-after-free / double-free in c-ares query-completion handling, remotely triggerable via ares_getaddrinfo() over TCP
Source: CVE Program / CVE List V5
Vulnerability 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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
双重释放
Source: CVE Program / CVE List V5
Vulnerability Title
c-ares 资源管理错误漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
c-ares是c-ares组织开源的一个用于异步 DNS 请求的 C 库。 c-ares 1.32.3版本至1.34.7之前版本存在资源管理错误漏洞，该漏洞源于查询完成处理中的释放后重用和双重释放问题，可能导致释放后重用或双重释放。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
c-ares c-ares >= 1.32.3, < 1.34.7 -

II. Public POCs for CVE-2026-33630

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III. Intelligence Information for CVE-2026-33630

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Patches & Fixes for CVE-2026-33630 (3)

Vendor Advisories for CVE-2026-33630 (1)

Vendor Pages for CVE-2026-33630 (1)

IV. Related Vulnerabilities

Same product: c-ares
Same vendor: c-ares
Same weakness: CWE-415