# CVE-2021-28089: tor: Tor before 0.4.5.7 allows a remote participant in the Tor directory protocol to exhaust CPU resources on a target, ak...

CVE-2021-28089 is fixed in 2 products on 1 platform, first by tor 0.3.2.10-1ubuntu0.2~esm2, released August 29, 2021. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2021-28089
- Priority: Routine
- CVSS: n/a (Medium)
- EPSS: 0.0167
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Mar 18, 2021

## Description

Tor before 0.4.5.7 allows a remote participant in the Tor directory protocol to exhaust CPU resources on a target, aka TROVE-2021-001.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | tor Ubuntu 18.04.6 LTS (bionic) | 0.3.2.10-1ubuntu0.2~esm2 | [tor 0.3.2.10-1ubuntu0.2~esm2](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-tor-0.3.2.10-1ubuntu0.2-esm2.md) | Aug 29, 2021 |
| Linux | tor Ubuntu 20.04 LTS (focal) | 0.4.2.7-1ubuntu0.1~esm1 | [tor 0.4.2.7-1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-tor-0.4.2.7-1ubuntu0.1-esm1.md) | Aug 29, 2021 |
| Linux | tor-geoipdb Ubuntu 18.04.6 LTS (bionic) | 0.3.2.10-1ubuntu0.2~esm2 | [tor-geoipdb 0.3.2.10-1ubuntu0.2~esm2](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-tor-geoipdb-0.3.2.10-1ubuntu0.2-esm2.md) | Aug 29, 2021 |
| Linux | tor-geoipdb Ubuntu 20.04 LTS (focal) | 0.4.2.7-1ubuntu0.1~esm1 | [tor-geoipdb 0.4.2.7-1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-tor-geoipdb-0.4.2.7-1ubuntu0.1-esm1.md) | Aug 29, 2021 |

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Data as of 2026-11-08T00:53:09Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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