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Fencer Vulns
high 8.3

CVE-2026-55427 json

Coder vulnerable to SSH config injection via unsanitized server-supplied values in `coder config-ssh`

published 2026-07-06 4 mo ago modified 2026-07-08 4 mo ago also GHSA-mcqq-fqgf-rxwm , GO-2026-5913 , EUVD-2026-42133

cvss
8.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 40%
public exploits
0
none known

Summary

Coder allows organizations to provision remote development environments via Terraform. Prior to versions 2.29.7, 2.32.7, 2.33.8, and 2.34.2, `coder config-ssh` wrote server-supplied SSH settings (`HostnameSuffix`, `SSHConfigOptions`) into the user's `~/.ssh/config` without sanitizing embedded newlines or restricting directives so a malicious or compromised Coder server could inject arbitrary SSH configuration. Practical exploitation requires control of the server-supplied values through a malicious or compromised deployment, a man-in-the-middle position or admin access to the `HostnameSuffix` and `SSHConfigOptions` settings. The fix in versions 2.29.7, 2.32.7, 2.33.8, and 2.34.2 validates `HostnameSuffix` and `SSHConfigOptions` against a strict character set that rejects newlines and other control characters. As a workaround, inspect `coder config-ssh --dry-run` output before applying changes.

Patch / fix

  • go github.com/coder/coder/v2 2.29.17, 2.32.7, 2.33.8, 2.34.2
  • coder coder 2.29.17, 2.32.7, 2.33.8, 2.34.2
  • govulncheck-vulndb openSUSE Leap 16.0 0.0.20260723T184607-160000.1.1

opensuse advisories openSUSE-SU-2026:21483-1

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
4 mo ago

Exploit prediction

0.47% chance of exploitation in the next 30 days, higher than 40% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 8.3 CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:H
GitHub 3.1 8.3 CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:H

Affected packages

ecosystem package affected fixed in
go github.com/coder/coder/v2
>=2.34.0, <2.34.2
>=2.33.0, <2.33.8
>=2.30.0, <2.32.7
<2.29.17
2.34.2
2.33.8
2.32.7
2.29.17
go github.com/coder/coder
all versions
 no fix listed

Affected products

  • coder coder

Classification

Weakness
  • CWE-74 Improper Neutralization of Special Elements in Output Used by a Downstream Component
  • CWE-78 Improper Neutralization of Special Elements used in an OS Command

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.