Medium severity · published Dec 3, 2025
CVE-2025-61727
Improper application of excluded DNS name constraints when verifying wildcard names in crypto/x509
6.5
CVSS
0.3%
EPSS
No
On KEV
Description
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
Low
Integrity
Low
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 21% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
CR
crypto/x509 · Go standard library
before 1.24.11; 1.25.0 before 1.25.5 · source: vendor
GO
GO · Golang
before 1.24.11; 1.25 before 1.25.5 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2025-61727
CVE.org
https://www.cve.org/CVERecord?id=CVE-2025-61727
Patch
https://go.dev/cl/723900
Issue Tracking
https://go.dev/issue/76442
Mailing List
https://groups.google.com/g/golang-announce/c/8FJoBkPddm4
Vendor Advisory
https://pkg.go.dev/vuln/GO-2025-4175
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