CVE-2026-56855
highpriority · track · 0EPSS 0.005 · 43 %ileFRUSEPSS · scored 2026-10-28
Previously, after a channel has been established, a malicious peer could send crafted messages that would deadlock the entire connection. Now, we handle all RFC 4254 channel messages; global requests are handled explicitly. Then, treat all other messages as a protocol error and tear the connection down instead of buffering and blocking.
cvss
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 6.9–7.5
ssvc
A stakeholder decision — act, attend, or track — from exploitation and impact.
weaknesses
The CWE weakness classes this flaw belongs to.
affected products (2)
Products and version ranges known to be affected.
advisories (2)
Vendor and ecosystem advisories describing this.
- CERTFR-2026-AVI-1385Multiples vulnérabilités dans les produits VMwareFrançais2026-10-26vendor · certfrFR
- GO-2026-6355Prevent DoS on deadlocked established channel in golang.org/x/crypto/ssh2026-09-02vendor · osvUS
Previously, after a channel has been established, a malicious peer could send crafted messages that would deadlock the entire connection. Now, we handle all RFC 4254 channel messages; global requests are handled explicitly. Then, treat all other messages as a protocol error and tear the connection down instead of buffering and blocking.
sources
Which sources assert this record, and when.
references (4) nvd
External citations — patches, advisories, analysis.
- https://go.dev/cl/826524Patch
- https://go.dev/issue/81317Issue TrackingVendor Advisory
- https://groups.google.com/g/golang-announce/c/1y3fb2np35UMailing ListVendor Advisory
- https://pkg.go.dev/vuln/GO-2026-6355Vendor Advisory
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