CVE-2026-55430

What it is

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, the workspace app proxy resolves the target app from `httpapi.RequestHost()` which prefers the `X-Forwarded-Host` header over the real `Host` header. No middleware strips `X-Forwarded-Host` before routing and the header is not browser-forbidden so client-side JavaScript can set it on `fetch()` calls. Practical exploitation requires subdomain app routing (wildcard hostname) enabled, a victim who visits the attacker's shared app and a deployment whose upstream proxy does not strip `X-Forwarded-Host`. The fix in versions 2.29.7, 2.32.7, 2.33.8, and 2.34.2 trusts `X-Forwarded-Host` only from configured trusted proxies and otherwise resolves the routing host from the verified request host. As a workaround, place an upstream reverse proxy that strips or overwrites `X-Forwarded-Host` on untrusted requests.

At a glance

Exploitability

Can be exploited over the network with a low-privilege account, but needs a user to act. High risk of data exposure.

Exploit odds

0.2% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2026-07-08 01:16 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-07-08 19:43 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.2% in the next 30 days (EPSS).
• Severity: 5.8 MEDIUM (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2026-07-08 01:16 UTC

Last modified

2026-07-08 19:43 UTC

Exploit probability

0.2% · EPSS, next 30 days

Weakness

CWE-345

Record status

Analyzed

Affected

• Coder < 2.29.17
• Coder < 2.32.7
• Coder < 2.33.8
• Coder < 2.34.2

Attack profile CVSS 3.1 · 5.8

Attack vector

Network

Complexity

High

Privileges needed

Low

User interaction

Required

Scope

Changed

Confidentiality

High

Integrity

None

Availability

None

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2026-55430.md and follow it. Check whether this project is affected by CVE-2026-55430. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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