Amazon Linux 2 Security Advisory: ALAS2-2025-3118
Advisory Released Date: 2026-01-05
Advisory Updated Date: 2026-01-05
crypto/x509: excluded subdomain constraint does not restrict wildcard SANs
An excluded subdomain constraint in a certificate chain does not restrict the usage of wildcard SANs in the leaf certificate. For example a constraint that excludes the subdomain test.example.com does not prevent a leaf certificate from claiming the SAN *.example.com. (CVE-2025-61727)
Within HostnameError.Error(), when constructing an error string, there is no limit to the number of hosts that will be printed out. Furthermore, the error string is constructed by repeated string concatenation, leading to quadratic runtime. Therefore, a certificate provided by a malicious actor can result in excessive resource consumption. (CVE-2025-61729)
Affected Packages:
golang-github-cpuguy83-go-md2man
Note:
This advisory is applicable to Amazon Linux 2 (AL2) Core repository. Visit this FAQ section for the difference between AL2 Core and AL2 Extras advisories.
Issue Correction:
Run yum update golang-github-cpuguy83-go-md2man or yum update --advisory ALAS2-2025-3118 to update your system.
aarch64:
golang-github-cpuguy83-go-md2man-1.0.4-4.amzn2.0.3.aarch64
src:
golang-github-cpuguy83-go-md2man-1.0.4-4.amzn2.0.3.src
x86_64:
golang-github-cpuguy83-go-md2man-1.0.4-4.amzn2.0.3.x86_64