CVE-2023-28320 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.