An improper certificate validation vulnerability exists in curl <v8.1.0 in the way it supports matching of wildcard patterns when listed as "Subject Alternative Name" in TLS server certificates. curl can be built to use its own name matching function for TLS rather than one provided by a TLS library. This private wildcard matching function would match IDN (International Domain Name) hosts incorrectly and could as a result accept patterns that otherwise should mismatch. IDN hostnames are converted to puny code before used for certificate checks. Puny coded names always start with `xn--` and should not be allowed to pattern match, but the wildcard check in curl could still check for `x*`, which would match even though the IDN name most likely contained nothing even resembling an `x`.
Fix
Patch, vendor advisory and mitigation references on NVD 2
- https://hackerone.com/reports/1950627 Exploit, Patch, Third Party Advisory
- https://hackerone.com/reports/1950627 Exploit, Patch, Third Party Advisory
Every line above is quoted from NVD, CISA, Microsoft, the vendor's own advisory or DISA; nothing is generated.
Change history 1
- First seenCVSS 5.9 · haxx, debian, fedoraprojectNVD modified 2026-10-23 23:10
Affected (CPE criteria) 11
cpe:2.3:a:haxx:curl:*:*:*:*:*:*:*:*cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*cpe:2.3:o:fedoraproject:fedora:37:*:*:*:*:*:*:*cpe:2.3:o:fedoraproject:fedora:38:*:*:*:*:*:*:*cpe:2.3:a:netapp:clustered_data_ontap:-:*:*:*:*:*:*:*cpe:2.3:a:netapp:ontap_antivirus_connector:-:*:*:*:*:*:*:*cpe:2.3:o:netapp:h300s_firmware:-:*:*:*:*:*:*:*cpe:2.3:o:netapp:h500s_firmware:-:*:*:*:*:*:*:*cpe:2.3:o:netapp:h700s_firmware:-:*:*:*:*:*:*:*cpe:2.3:o:netapp:h410s_firmware:-:*:*:*:*:*:*:*cpe:2.3:o:apple:macos:*:*:*:*:*:*:*:*
References 24
- http://seclists.org/fulldisclosure/2023/Jul/47 Mailing List, Third Party Advisory
- http://seclists.org/fulldisclosure/2023/Jul/48 Mailing List, Third Party Advisory
- http://seclists.org/fulldisclosure/2023/Jul/52 Mailing List, Third Party Advisory
- https://hackerone.com/reports/1950627 Exploit, Patch, Third Party Advisory
- https://lists.debian.org/debian-lts-announce/2023/10/msg00016.html Mailing List, Third Party Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/F4I75RDGX5ULSSCBE5BF3P5I5SFO7ULQ/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/Z2LIWHWKOVH24COGGBCVOWDXXIUPKOMK/
- https://security.gentoo.org/glsa/202310-12 Third Party Advisory
- https://security.netapp.com/advisory/ntap-20230609-0009/ Third Party Advisory
- https://support.apple.com/kb/HT213843 Third Party Advisory
- https://support.apple.com/kb/HT213844 Third Party Advisory
- https://support.apple.com/kb/HT213845 Third Party Advisory
- http://seclists.org/fulldisclosure/2023/Jul/47 Mailing List, Third Party Advisory
- http://seclists.org/fulldisclosure/2023/Jul/48 Mailing List, Third Party Advisory
- http://seclists.org/fulldisclosure/2023/Jul/52 Mailing List, Third Party Advisory
- https://hackerone.com/reports/1950627 Exploit, Patch, Third Party Advisory
- https://lists.debian.org/debian-lts-announce/2023/10/msg00016.html Mailing List, Third Party Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/F4I75RDGX5ULSSCBE5BF3P5I5SFO7ULQ/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/Z2LIWHWKOVH24COGGBCVOWDXXIUPKOMK/
- https://security.gentoo.org/glsa/202310-12 Third Party Advisory
- https://security.netapp.com/advisory/ntap-20230609-0009/ Third Party Advisory
- https://support.apple.com/kb/HT213843 Third Party Advisory
- https://support.apple.com/kb/HT213844 Third Party Advisory
- https://support.apple.com/kb/HT213845 Third Party Advisory