GO-2026-6354: golang.org/x/crypto (CVE-2026-78662)

Prevent DoS on deadlocked undecided channel in golang.org/x/crypto/ssh

CVSS 7.5 HighEPSS 0.0043 · 37th percentile

Published by OSV at 2 Sept 2026, 19:12 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

Package	Ecosystem	Affected	Fixed in
golang.org/x/crypto	Go	<0.56.0	0.56.0

Identifiers

GO-2026-6354 · CVE-2026-78662

Weakness (CWE)

CWE-770

Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

Golang.org/x/crypto/ssh is vulnerable in versions before 0.56.0. A malicious peer can flood a channel that has not yet been established, which deadlocks the whole SSH connection. Upgrade golang.org/x/crypto to version 0.56.0 or later.

Written 6 Nov 2026.

Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

Severity and exploitation

Score	Rating	CVSS	Vector	Source
7.5	High	3.1	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N	ADP (CISA-ADP)

CISA KEV Not listed.
EPSS 0.0043, the 37th percentile, on 14 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

31 Oct 2026, 14:46 UTC First seen by agentprime
31 Oct 2026, 14:46 UTC Confirmed by OSV

Sources

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.