golang.org/x/crypto/ssh · Prevent DoS on Deadlocked Established Channel
Affects MicrosoftSource GCVE Database
Not known to be exploited · CVSS 7.5 High : upgrade to 0.56.0 soon.
Data as of 31 Oct 2026, 08:36 UTC
- EPSS
- 0.5% chance of exploitation in 30 days – higher than 42% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 0.56.0
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 2 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.
What to do
Upgrade golang.org/x/crypto/ssh to 0.56.0.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| golang.org/x/cryptogolang.org/x/crypto/ssh | Affected
| Fixed in
|
Gogolang.org/x/crypto/sshpkg:golang/golang.org/x/crypto/sshOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
Description
CVE-2026-56855 is a vulnerability in golang.org/x/crypto/ssh that can cause a denial of service (DoS) due to a deadlocked established channel. It affects versions 3.0 and 4.0 of the Microsoft product using this library. No CVSS score or detailed impact information is provided.