Panic when processing post-handshake message on QUIC connections in crypto/tls

HIGH 7.5CVE-2023-39321 · BIT-golang-2023-39321 · GO-2023-2044 · Published 08/09/2023 · updated 17/06/2026

In short

CVE-2023-39321 is a HIGH (CVSS 7.5) vulnerability affecting stdlib, go (golang).
Chance of exploitation in the next 30 days (EPSS): 1.3%, higher than 71.4% of all vulnerabilities.
Fix: update to 1.21.1 or later.

Package	Affected versions	Patched versions
stdlib Go	`≥ 1.21.0-0, < 1.21.1`	`1.21.1`
go golang	`≥ 1.21.0, < 1.21.1`	`1.21.1`

Processing an incomplete post-handshake message for a QUIC connection can cause a panic.

NVD description

Processing an incomplete post-handshake message for a QUIC connection can cause a panic.

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Package

Affected versions

Patched versions

≥ 1.21.0-0, < 1.21.1

1.21.1

≥ 1.21.0, < 1.21.1

1.21.1

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