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.

References

• https://nvd.nist.gov/vuln/detail/CVE-2023-28320
• https://hackerone.com/reports/1929597
• https://support.apple.com/kb/HT213843
• https://support.apple.com/kb/HT213844
• https://support.apple.com/kb/HT213845
• http://seclists.org/fulldisclosure/2023/Jul/47
• http://seclists.org/fulldisclosure/2023/Jul/48
• http://seclists.org/fulldisclosure/2023/Jul/52
• https://security.gentoo.org/glsa/202310-12
• https://security.netapp.com/advisory/ntap-20230609-0009