What is CVE-2025-61729?

CVE-2025-61729 is a high-severity vulnerability in Golang Go, classified under Improper Certificate Validation. CVSS score: 7.5/10. Published 2025-12-02.

How severe is CVE-2025-61729?

High severity. CVSS v3 base score is 7.5 out of 10.

Vulnerability in Golang Go

CVE-2025-61729

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 class: Improper Certificate Validation

Published 2025-12-02 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.005 (37.2th percentile), scored 2026-09-30.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 37th percentile — 37.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.005 · newest: 0.005 · change: 0.000

Affected products

Golang Go
Go Standard Library Crypto/x509 — versions 0, 1.25.0

Weakness classification (CWE)

CWE-295 — Improper Certificate Validation

References

go.dev/cl/725920 (Patch)
go.dev/issue/76445 (Patch, Issue Tracking)
groups.google.com/g/golang-announce/c/8FJoBkPddm4 (Mailing List, Release Notes)
pkg.go.dev/vuln/GO-2025-4155 (Vendor Advisory)

Frequently asked questions

What is CVE-2025-61729?: CVE-2025-61729 is a high-severity vulnerability in Golang Go, classified under Improper Certificate Validation. CVSS score: 7.5/10. Published 2025-12-02.
How severe is CVE-2025-61729?: High severity. CVSS v3 base score is 7.5 out of 10.