Denial of Service Vulnerability in libcurl's Synchronous Resolver

CVE-2023-28320 · MEDIUM Severity

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

A denial of service vulnerability exists in curl <v8.1.0 in the way libcurl provides several different backends for resolving host names, selected at build time. If it is built to use the synchronous resolver, it allows name resolves to time-out slow operations using `alarm()` and `siglongjmp()`. When doing this, libcurl used a global buffer that was not mutex protected and a multi-threaded application might therefore crash or otherwise misbehave.

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