CVE-2025-61729: go Cert Validation Flaw — Fix

Description

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.

Is your site exposed to CVE-2025-61729?

Run a free security scan — no signup, results in seconds.

CVSS v3.1 Score

7.5

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Weakness Type (CWE)

CWE-295 CWE-295

Affected Products

Vendor	Product	Versions
golang	go	< 1.24.11
golang	go	1.25.0 — 1.25.5

References

Advisories & Patches

https://go.dev/cl/725920 https://go.dev/issue/76445 https://pkg.go.dev/vuln/GO-2025-4155

Other References

https://groups.google.com/g/golang-announce/c/8FJoBkPddm4

Frequently Asked Questions

What is 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. It has a CVSS v3.1 base score of 7.5 (HIGH).

How severe is CVE-2025-61729? +

CVE-2025-61729 has a CVSS v3.1 score of 7.5 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching.

What products are affected by CVE-2025-61729? +

CVE-2025-61729 affects products from golang, specifically: go. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-61729? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

Related Vulnerabilities

CVE-2026-44700

Elixir WebRTC is an Elixir implementation of the W3C WebRTC API. Prior to 0.15.1 and 0.16.1, missing DTLS peer certificate …

CVE-2026-0277

An improper certificate validation vulnerability in the Prisma® Access Agent for iOS enables an attacker to perform a man-in-the-middle (MitM) …

CVE-2025-3463

"This issue is limited to motherboards and does not affect laptops, desktop computers, or other endpoints." An insufficient validation vulnerability …

CVE-2025-5279

When the Amazon Redshift Python Connector is configured with the BrowserAzureOAuth2CredentialsProvider plugin, the driver skips the SSL certificate validation step …

CVE-2025-34066

An improper certificate validation vulnerability exists in AVTECH IP cameras, DVRs, and NVRs due to the use of wget with …

CVE-2025-7395

A certificate verification error in wolfSSL when building with the WOLFSSL_SYS_CA_CERTS and WOLFSSL_APPLE_NATIVE_CERT_VALIDATION options results in the wolfSSL client failing …

CVE-2025-61729