CVE-2026-56855CWE-770denial-of-service

CVE-2026-56855

High · published September 3, 2026

CVSS v3.1
7.5
EPSS
1%
Percentile
41.9
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
7.5 · HIGH
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS v4.0
Not supplied
EPSS
0.00500 · 41.9th percentile
Weakness
CWE-770 · Allocation of Resources Without Limits or Throttling
Published
2026-09-03T00:17Z
Affected products (1)
ProductVersionsFixed in
golang/crypto< 0.56.00.56.0
References (4)
https://go.dev/cl/826524 · [email protected]https://go.dev/issue/81317 · [email protected]https://groups.google.com/g/golang-announce/c/1y3fb2np35U · [email protected]https://pkg.go.dev/vuln/GO-2026-6355 · [email protected]
EPSS history
Timeline
  • 04 SEP 03:42Z
    EPSS moved — → 0%
    epss
  • 02 SEP 19:37Z
    Prevent DoS on deadlocked established channel in golang.org/x/crypto/ssh
    cvelistv5