# CVE-2018-20482: tar: GNU Tar through 1.30, when --sparse is used, mishandles file shrinkage during read access, which allows local users t...

CVE-2018-20482 is fixed in 2 products on 1 platform, first by tar 1.29b-2ubuntu0.2, released March 22, 2019. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2018-20482
- Priority: Routine
- CVSS: n/a (Low)
- EPSS: 0.0053
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Dec 26, 2018

## Description

GNU Tar through 1.30, when --sparse is used, mishandles file shrinkage during read access, which allows local users to cause a denial of service (infinite read loop in sparse_dump_region in sparse.c) by modifying a file that is supposed to be archived by a different user's process (e.g., a system backup running as root).

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | tar Ubuntu 18.04.6 LTS (bionic) | 1.29b-2ubuntu0.2 | [tar 1.29b-2ubuntu0.2](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-tar-1.29b-2ubuntu0.2.md) | Mar 22, 2019 |
| Linux | tar-scripts Ubuntu 18.04.6 LTS (bionic) | 1.29b-2ubuntu0.2 | [tar-scripts 1.29b-2ubuntu0.2](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-tar-scripts-1.29b-2ubuntu0.2.md) | Mar 22, 2019 |

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Data as of 2026-11-07T12:40:37Z 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 Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo