CVE-2025-68121

CRITICAL 9.1

Unexpected session resumption in crypto/tls

CVSS Score

9.1

EPSS Score

0.0%

EPSS Percentile

5th

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.

Vendor	go standard library
Product	crypto/tls
Published	Feb 5, 2026
Last Updated	Apr 29, 2026

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Affected Versions

Go standard library / crypto/tls

0 < 1.24.13 1.25.0-0 < 1.25.7 1.26.0-rc.1 < 1.26.0-rc.3

References

NVD ↗ CVE.org ↗ EPSS Data ↗

groups.google.com: https://groups.google.com/g/golang-announce/c/K09ubi9FQFk go.dev: https://go.dev/cl/737700 go.dev: https://go.dev/issue/77217 pkg.go.dev: https://pkg.go.dev/vuln/GO-2026-4337

Credits

Coia Prant (github.com/rbqvq) Go Security Team