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Vulnerability record · CVE-2025-68121 · published 5 February 2026

CVE-2025-68121: Golang go improper certificate validation vulnerability

Golang · Go

During session resumption in crypto/tls, if the underlying Config has its ClientCAs or RootCAs fields mutated between the initial handshake and the resumed handshake, the resumed handshake may succeed when it should have failed. This may happen when a user calls Config.Clone and mutates the returned Config, or uses Config.GetConfigForClient. This can cause a client to resume a session with a server that it would not have resumed with during the initial handshake, or cause a server to resume a session with a client that it would not have resumed with during the initial handshake.

10.0 CVSS 3.1 Critical EPSS 0.86% · top 43.3% CWE-295 · Improper certificate validation
10.0CVSS 3.1 base score
0.86%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
4References, 1 tagged exploit
17 Jun 2026Last modified by NVD

Description

During session resumption in crypto/tls, if the underlying Config has its ClientCAs or RootCAs fields mutated between the initial handshake and the resumed handshake, the resumed handshake may succeed when it should have failed. This may happen when a user calls Config.Clone and mutates the returned Config, or uses Config.GetConfigForClient. This can cause a client to resume a session with a server that it would not have resumed with during the initial handshake, or cause a server to resume a session with a client that it would not have resumed with during the initial handshake.

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

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://go.dev/cl/737700 Patch
https://go.dev/issue/77217 ExploitIssue Tracking
https://groups.google.com/g/golang-announce/c/K09ubi9FQFk Mailing ListThird Party Advisory
https://pkg.go.dev/vuln/GO-2026-4337 Vendor Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2025-68121), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.