CVE-2026-56862

UNKNOWN 0.0

Limit handshake messages we are willing to accept post-handshake in crypto/tls

CVSS Score

0.0

EPSS Score

0.0%

EPSS Percentile

0th

Handshake messages, such as KeyUpdate, are always considered as state-advancing, regardless of whether a handshake has been completed or not. As a result, a malicious client can keep sending KeyUpdate messages to force the server to keep performing key derivation operations indefinitely.

Vendor	go standard library
Product	crypto/tls
Published	Aug 13, 2026

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Affected Versions

Go standard library / crypto/tls

0 < 1.25.13 1.26.0-0 < 1.26.6 1.27.0-0 < 1.27.0-rc.3

References

NVD ↗ CVE.org ↗ EPSS Data ↗

go.dev: https://go.dev/issue/80528 go.dev: https://go.dev/cl/804261 groups.google.com: https://groups.google.com/g/golang-announce/c/94pEornpRlI pkg.go.dev: https://pkg.go.dev/vuln/GO-2026-6090

Credits

Qi Deng of Aurascape.ai