CVE-2026-39834

Invoking infinite loop on large channel writes in golang.org/x/crypto/ssh

State: Published
Severity: 9.1 Critical
Published: May 22, 2026
Updated: May 22, 2026
Reserved: Apr 7, 2026

Description

When writing data larger than 4GB in a single Write call on an SSH channel, an integer overflow in the internal payload size calculation caused the write loop to spin indefinitely, sending empty packets without making progress. The size comparison now uses int64 to prevent truncation.

Scores

CVSS	Score	Vector	Source
3.1	9.1 Critical	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H	CISA-ADP

Weaknesses

The record names no weakness.

Affected Products

Product	Versions
golang.org/x/crypto/sshgolang.org/x/crypto	before 0.52.0Affected

References

https://go.dev/issue/79567
https://groups.google.com/g/golang-announce/c/a082jnz-LvI
https://go.dev/cl/781663
https://pkg.go.dev/vuln/GO-2026-5020

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