---
title: CVE-2021-42771
description: Ubuntu is an open source software operating system that runs from the
  desktop, to the cloud, to all your internet connected things.
url: https://ubuntu.com/security/CVE-2021-42771
---

# CVE-2021-42771

Publication date 20 October 2021

Last updated 25 August 2025

---

Ubuntu priority

**Medium**

[Why this priority?](https://ubuntu.com/security/cves/about#priority )

## Cvss 3 Severity Score

**7.8 · High**

[Score breakdown](https://ubuntu.com/security/CVE-2021-42771#impact-score)

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## Description

Babel.Locale in Babel before 2.9.1 allows attackers to load arbitrary
locale .dat files (containing serialized Python objects) via directory
traversal, leading to code execution.

[Read the notes from the security team](https://ubuntu.com/security/CVE-2021-42771#notes)

## Status

Show unmaintained releases

| Package | Ubuntu Release | Status |
| --- | --- | --- |
| python-babel | 22.04 LTS jammy | Not affected |
| 21.10 impish | Not affected |
| 21.04 hirsute | Not affected |
| 20.04 LTS focal | Not affected |
| 18.04 LTS bionic | Not affected |
| 16.04 LTS xenial | Not affected |
| 14.04 LTS trusty | Not affected |

---

* [How can I get the fixes?](https://ubuntu.com/security/cves/about#security)
* [What do statuses mean?](https://ubuntu.com/security/cves/about#statuses)
* [Patch details](https://ubuntu.com/security/CVE-2021-42771#patch-details)

## Notes

---

### [leosilva](https://launchpad.net/~leosilva)

fixed as CVE-2021-20095. But that CVE number was rejected and that
new one was assigned to that issue.

### Patch details

For informational purposes only. We recommend not to cherry-pick updates. [How can I get the fixes?](https://ubuntu.com/security/cves/about#security)

| Package | Patch details |
| --- | --- |
| python-babel | * Upstream:   <https://github.com/python-babel/babel/pull/782/commits/3a700b5b8b53606fd98ef8294a56f9510f7290f8> * Upstream:   <https://github.com/python-babel/babel/pull/782/commits/5caf717ceca4bd235552362b4fbff88983c75d8c> |

## Severity score breakdown

CVSS version:
CVSS v3.0

**Base score**

7.8 · High

* Base metrics

  | Parameter | Value |
  | --- | --- |
  | Attack vector | Local |
  | Attack complexity | Low |
  | Privileges required | Low |
  | User interaction | None |
  | Scope | Unchanged |
  | Confidentiality impact | High |
  | Integrity impact | High |
  | Availability impact | High |
* Scores

  | Parameter | Value |
  | --- | --- |
  | Base score | 7.8 · High |
  | Exploitability score | - |
  | Impact score | - |

**Vector:** CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

## References

* [MITRE](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-42771)
* [NVD](https://nvd.nist.gov/vuln/detail/CVE-2021-42771)
* [Launchpad](https://launchpad.net/bugs/cve/CVE-2021-42771)
* [Debian](https://security-tracker.debian.org/tracker/CVE-2021-42771)

### Other references

* <https://www.tenable.com/security/research/tra-2021-14>
* <https://github.com/python-babel/babel/pull/782>
* <https://lists.debian.org/debian-lts/2021/10/msg00040.html>
* <https://lists.debian.org/debian-lts-announce/2021/10/msg00018.html>
* <https://www.cve.org/CVERecord?id=CVE-2021-42771>