CVE-2025-61729
HighCVSS 7.5Exploitation Probability (EPSS)
Low risk38th percentile - higher than 38% of all known CVEs
Summary
Within HostnameError.Error(), there is no limit to the number of hosts printed when constructing an error string, and the string is built by repeated concatenation, leading to quadratic runtime. A certificate provided by a malicious actor can result in excessive resource consumption.
Risk Assessment
An attacker can supply a crafted certificate to cause excessive CPU and memory consumption, leading to a partial denial of service.
Recommendation
Update the library to a version that limits the number of printed hosts and optimizes error string construction.
Other vulnerabilities in Go crypto/x509
See all- CVE-2026-111943Unknown
The Go standard library (crypto/x509) added a denylist of known intermediate certificates no longer considered trustworthy. This defends against cases where system trust stores may not be updated without further action.
- CVE-2026-32280High
During chain building, the amount of work is not correctly limited when a large number of intermediate certificates are passed in VerifyOptions.Intermediates, which can lead to denial of service. This affects both direct users of crypto/x509 and users of crypto/tls.
Original NVD description (English source)
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.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS