PT-2023-3462 · Curl+11 · Curl+11
Hiroki Kurosawa
·
Published
2023-05-17
·
Updated
2026-05-18
·
CVE-2023-28321
CVSS v3.1
5.9
Medium
| Vector | AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N |
Name of the Vulnerable Software and Affected Versions
curl versions prior to 8.1.0
Description
The issue is related to improper certificate validation in the way curl supports matching of wildcard patterns when listed as "Subject Alternative Name" in TLS server certificates. This could lead to incorrect matching of IDN hosts and potentially allow patterns that should mismatch. IDN hostnames are converted to puny code before being used for certificate checks, but the wildcard check in curl could still incorrectly match patterns. This could result in a remote attacker being able to perform a "man-in-the-middle" attack.
Recommendations
For versions prior to 8.1.0, update to version 8.1.0 or later to resolve the issue. As a temporary workaround, consider disabling the use of wildcard patterns in TLS server certificates until a patch is available. Restrict access to IDN hostnames to minimize the risk of exploitation. Avoid using the
xn-- prefix in wildcard patterns to prevent incorrect matching.Exploit
Fix
Improper Certificate Validation
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Weakness Enumeration
Related Identifiers
Affected Products
Alt Linux
Almalinux
Astra Linux
Centos
Linuxmint
Apple Macos
Red Hat
Red Os
Rocky Linux
Suse
Ubuntu
Curl