# CVE-2021-33880: Observable Timing Discrepancy in aaugustin websockets library

> An attacker can guess passwords via timing attacks when HTTP Basic Authentication is enabled in the Python websockets library.

- **Severity:** Medium 5.9 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 6 Jun 2021
- **Updated:** 4 Aug 2024
- **Also known as:** CLSA-2025-1764115973, DEBIAN-CVE-2021-33880, GHSA-8ch4-58qp-g3mp, PYSEC-2021-95, UBUNTU-CVE-2021-33880

## What is CVE-2021-33880?

CVE-2021-33880 is a medium-severity vulnerability in Oracle Communications Cloud Native Core Policy, published on 6 Jun 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official 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.

Weakness: CWE-203 (Observable Discrepancy)

## Which versions are affected by CVE-2021-33880?

3 open source packages ship an affected version, including websockets. It affects 5 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `websockets` | PyPI | All versions | 9.1 |
| `websockets` | PyPI | All versions | 9.1 |
| `websockets` | PyPI | All versions | 9.1 |

Products: Oracle Communications Cloud Native Core Policy, Oracle Communications Cloud Native Core Security Edge Protection Proxy, Oracle Communications Cloud Native Core Service Communication Proxy, Oracle Communications Cloud Native Core Unified Data Repository, Websockets Project Websockets.

## How do I fix CVE-2021-33880?

Upgrade websockets to 9.1 or later.

## Is CVE-2021-33880 being exploited?

There is no known exploitation of CVE-2021-33880 in the wild and no public exploit code.

## Other vulnerabilities in Oracle Communications Cloud Native Core Policy

- [CVE-2021-35574](https://insights.sbomify.com/CVE-2021-35574/): Denial of service in Outside In Technology (high 7.5)
- [CVE-2021-22119](https://insights.sbomify.com/CVE-2021-22119/): Resource Exhaustion in Spring Security (high 7.5)
- [CVE-2021-23440](https://insights.sbomify.com/CVE-2021-23440/): Prototype Pollution (high 7.3)
- [CVE-2019-3799](https://insights.sbomify.com/CVE-2019-3799/): Directory Traversal with spring-cloud-config-server (medium 6.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-33880 and fix it if it is affected.

What it is: CVE-2021-33880 is a medium-severity vulnerability in Oracle Communications Cloud Native Core Policy, published on 6 Jun 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-33880 in the wild and no public exploit code.

Affected packages and fixed versions:
- websockets (PyPI): affected all versions; fixed in 9.1
- websockets (PyPI): affected all versions; fixed in 9.1
- websockets (PyPI): affected all versions; fixed in 9.1

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-2021-33880/ (Markdown: https://insights.sbomify.com/CVE-2021-33880/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-33880
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-33880
- OSV: https://osv.dev/vulnerability/CVE-2021-33880

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-33880/
Summaries are generated and may contain mistakes; the official description above is the record.