CVE-2023-39322: Memory exhaustion in QUIC connection handling in crypto/tls

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2023-09-08 · updated 2026-06-17
Weakness: CWE-770

Description

QUIC connections do not set an upper bound on the amount of data buffered when reading post-handshake messages, allowing a malicious QUIC connection to cause unbounded memory growth. With fix, connections now consistently reject messages larger than 65KiB in size.

Affected products

Go: from 1.21.0 before 1.21.1 — fixed in 1.21.1

How to fix

Upgrade to a fixed version: Go 1.21.1. Check the vendor advisory for mitigations.

References

https://go.dev/cl/523039
https://go.dev/issue/62266
https://groups.google.com/g/golang-dev/c/2C5vbR-UNkI/m/L1hdrPhfBAAJ
https://pkg.go.dev/vuln/GO-2023-2045
https://security.gentoo.org/glsa/202311-09
https://security.netapp.com/advisory/ntap-20231020-0004/
https://go.dev/cl/523039
https://go.dev/issue/62266
https://groups.google.com/g/golang-dev/c/2C5vbR-UNkI/m/L1hdrPhfBAAJ
https://pkg.go.dev/vuln/GO-2023-2045
https://security.gentoo.org/glsa/202311-09
https://security.netapp.com/advisory/ntap-20231020-0004/

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