CVE-2026-55427 | Coder vulnerable to SSH config injection via unsanitized server-supplied values in `coder config-ssh`

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.

Published: 2026-07-07 Last update: 2026-07-08 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-55427 is rated Moderate Risk (46.3/100): CVSS High severity, with low exploitation likelihood (EPSS 0.47%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-55427

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-07-08 — 0.47% —

Full EPSS history (1 record total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-55427

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
8.3 3.1 HIGH
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.6 6.0 [email protected]

Weakness enumeration for CVE-2026-55427

GitHub Security Advisory for CVE-2026-55427

GHSA-mcqq-fqgf-rxwm · Severity: high · Ecosystem: go — Coder vulnerable to SSH config injection via unsanitized server-supplied values in `coder config-ssh`

Affected software / configurations for CVE-2026-55427

Vendor Product Version Raw CPE
coder coder < 2.29.17 cpe:2.3:a:coder:coder:*:*:*:*:*:go:*:*
coder coder >= 2.30.0, < 2.32.7 cpe:2.3:a:coder:coder:*:*:*:*:*:go:*:*
coder coder >= 2.33.0, < 2.33.8 cpe:2.3:a:coder:coder:*:*:*:*:*:go:*:*
coder coder >= 2.34.0, < 2.34.2 cpe:2.3:a:coder:coder:*:*:*:*:*:go:*:*

References for CVE-2026-55427

cvelogic Threat Intelligence