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VulnerabilityPublished

CVE-2026-55427: V2 · Coder vulnerable to SSH config injection via unsanitized server-supplied values in `coder config-ssh`

Affects github.com/coder/coder/v2Source GCVE Database

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Not known to be exploited · CVSS 8.3 High : upgrade to 2.34.2 soon.

Data as of 30 Oct 2026, 06:59 UTC

CVSS 3.1 base score
8.3High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.4% chance of exploitation in 30 days – higher than 40% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 2.34.2, 2.33.8, 2.32.7 +1
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 6 Jul 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq 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 29 Oct 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
Gogithub.com/coder/coder/v2Affected
  • >=2.34.0 <2.34.2
Fixed in
  • 2.34.2
Gogithub.com/coder/coder/v2Affected
  • >=2.33.0 <2.33.8
Fixed in
  • 2.33.8
Gogithub.com/coder/coder/v2Affected
  • >=2.30.0 <2.32.7
Fixed in
  • 2.32.7
Gogithub.com/coder/coder/v2Affected
  • <2.29.17
Fixed in
  • 2.29.17

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Apply the official patches available in Coder versions 2.34.2, 2.33.8, 2.32.7, and 2.29.17 or later, which validate and sanitize server-supplied SSH configuration values to prevent injection. As a workaround, inspect the output of `coder config-ssh --dry-run` before applying changes to detect any malicious configuration directives. No other mitigations are specifically recommended.

Description

### Summary `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. > **Note:** 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. ### Impact A server administrator or an attacker who controlled the server, could inject a directive such as `ProxyCommand` and achieve arbitrary code execution on any developer workstation that ran `coder config-ssh`. Injected commands ran with the local user's privileges and applied to all SSH connections, not just Coder workspaces. ### Patches The fix validates `HostnameSuffix` and `SSHConfigOptions` against a strict character set that rejects newlines and other control characters. The fix was backported to all supported release lines: | Release line | Patched version | |---|---| | 2.34 | [v2.34.2](https://github.com/coder/coder/releases/tag/v2.34.2) | | 2.33 | [v2.33.8](https://github.com/coder/coder/releases/tag/v2.33.8) | | 2.32 | [v2.32.7](https://github.com/coder/coder/releases/tag/v2.32.7) | | 2.29 (ESR) | [v2.29.17](https://github.com/coder/coder/releases/tag/v2.29.17) | ### Workarounds Inspect `coder config-ssh --dry-run` output before applying changes. ### Resources - Fix: #26154 ### Credits Coder would like to thank Anthropic's Security Team (ANT-2026-22437) for independently disclosing this issue!

References

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