high · 7.5 Patched

Quart leaks raw request body (incl. plaintext passwords) to stdout via stray debug print in Body.__await__

GHSA-v853-p72q-4cfw · published 5 Oct 2026

How serious is it

  • Severity: high, CVSS score 7.5 out of 10.
  • No exploit prediction (EPSS) score yet.
  • Not on the CISA list of exploited vulnerabilities.
  • No public exploit in Exploit-DB.

Is your app affected by GHSA-v853-p72q-4cfw?

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Who is affected

  • quart (PyPI) = 0.23.0

How to check

  1. Run pip show quart in your project to see the installed version, including copies pulled in by other packages.
  2. Or paste your lockfile into the checker: it lists every package with a known vulnerability, this one included.
  3. Or run npx shippable-dev scan localhost:3000 in your project folder. It reads your lockfile and flags this vulnerability along with every other known one.

How to fix

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  1. Upgrade quart to 0.23.1 or later, commit the lockfile and redeploy.
  2. If a vulnerable version was live, check your logs and rotate the secrets that server could read.

The advisory

### Summary Quart 0.23.0 contains a stray debug statement (`print(data)`) inside `Body.__await__` in `quart/wrappers/request.py`. Any request whose body is awaited — `await request.form`, `await request.get_data()`, WTForms `validate_on_submit()`, etc. — has its raw, unparsed body printed to stdout, including plaintext form fields such as passwords and CSRF tokens. Confirmed present in 0.23.0, confirmed absent in 0.22.0. ### Details In `src/quart/wrappers/request.py`, `Body.__await__` accumulates the request body into a bytearray: ​```python data = bytearray() while not self._queue.empty(): data.extend(self._queue.get_nowait()) print(data) # <-- not present in 0.22.0 if ( self._max_content_length is not None and len(data) > self._max_content_length ): raise RequestEntityTooLarge() ​``` This fires for every request that awaits its body — the overwhelming majority of POST/PUT routes in a typical Quart app (form submissions, JSON APIs via `request.get_json()`, file uploads, etc.). ### PoC 1. `pip install quart==0.23.0` (requires Python 3.13+) 2. Minimal route: ​```python @app.route("/login", methods=["POST"]) async def login(): form_data = await request.form ... ​``` 3. Submit a POST with form data, e.g. a login form with `staff_id`/`password` fields. 4. Observe stdout: the full raw body is printed as `bytearray(b'csrf_token=...&staff_id=...&password=...')`. Confirmed via source diff against 0.22.0's `request.py`, where this line does not exist. ### Impact Any app that captures stdout in logs (terminal redirect, systemd/journald, Docker logs, cloud log aggregation, etc.) will have every submitted form body — including login credentials — written to logs in plaintext. This affects any Quart 0.23.0 app handling authentication or any sensitive form data, and is trivially triggerable by any user simply submitting a form (no attacker action required beyond normal use).

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References

Merged from GitHub Advisory Database. Last updated 3 Nov 2026. All vulnerabilities · RSS · JSON