# CVE-2026-91201: DocsGPT through 0.20.0 OAuth Token Disclosure via Wildcard postMessage

> Attackers can steal OAuth session tokens via wildcard postMessage to access victim cloud storage connectors.

- **Severity:** Medium 5.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:N/VA:L/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 14 Sep 2026
- **Updated:** 24 Sep 2026
- **Also known as:** GHSA-x85x-q6hq-hm4x

## What is CVE-2026-91201?

CVE-2026-91201 is a medium-severity vulnerability in arc53 DocsGPT, published on 14 Sep 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

DocsGPT through 0.20.0 posts OAuth connector session tokens to a wildcard target origin in the callback-status endpoint without validating sender origin. Attackers can obtain session tokens and provider account emails by acting as window.opener during OAuth authorization, then use tokens to disconnect victims' cloud storage connectors.

Weakness: CWE-346 (Origin Validation Error)

## Which versions are affected by CVE-2026-91201?


## How do I fix CVE-2026-91201?

No fix has been published for CVE-2026-91201 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-91201 being exploited?

There is no known exploitation of CVE-2026-91201 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-91201 and fix it if it is affected.

What it is: CVE-2026-91201 is a medium-severity vulnerability in arc53 DocsGPT, published on 14 Sep 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-91201 in the wild and no public exploit code.

Affected product: arc53 DocsGPT. 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-2026-91201/ (Markdown: https://insights.sbomify.com/CVE-2026-91201/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-91201
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-91201
- OSV: https://osv.dev/vulnerability/CVE-2026-91201

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-91201/
Summaries are generated and may contain mistakes; the official description above is the record.