# CVE-2026-111927: Coder before 2.35.4 Credential Theft via Workspace Proxy Hostname Prefix Match

> Attackers can steal API keys via hostname prefix matching flaws, allowing unauthorized access to victim workspaces in Coder.

- **Severity:** High 8.7 (`CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:P/VC:H/VI:H/VA:N/SC:H/SI:H/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 17 Oct 2026
- **Updated:** 21 Oct 2026
- **Also known as:** GHSA-47cv-h282-xh6p, GHSA-h58h-qvv5-xvwg

## What is CVE-2026-111927?

CVE-2026-111927 is a high-severity authentication bypass vulnerability in coder, published on 17 Oct 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.

### Official description

Coder before 2.29.20, 2.33.0 before 2.33.12, 2.34.0 before 2.34.8, and 2.35.0 before 2.35.4 contains an improper hostname validation flaw in GetWorkspaceProxyByHostname whose SIMILAR TO pattern performs a prefix match, so any domain that is a string prefix of a workspace-proxy access URL is trusted as a proxy. Attackers owning such a domain can lure an authenticated victim to a crafted /api/v2/applications/auth-redirect link, capture the redirected application_connect API key, and replay it to access the victim's workspace apps.

Weakness: CWE-522 (Insufficiently Protected Credentials)

## Which versions are affected by CVE-2026-111927?


## How do I fix CVE-2026-111927?

No fix has been published for CVE-2026-111927 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-111927 being exploited?

There is no known exploitation of CVE-2026-111927 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-111927 and fix it if it is affected.

What it is: CVE-2026-111927 is a high-severity authentication bypass vulnerability in coder, published on 17 Oct 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-111927 in the wild and no public exploit code.

Affected product: coder. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-111927/ (Markdown: https://insights.sbomify.com/CVE-2026-111927/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-111927
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-111927
- OSV: https://osv.dev/vulnerability/CVE-2026-111927

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-111927/
Summaries are generated and may contain mistakes; the official description above is the record.