CVE-2021-21251: OneDev is an all-in-one devops platform. In OneDev before version 4.0.3 there is a critical "zip slip" vulnerability. This issue may lead to arbitrary...

Description

OneDev is an all-in-one devops platform. In OneDev before version 4.0.3 there is a critical "zip slip" vulnerability. This issue may lead to arbitrary file write. The KubernetesResource REST endpoint untars user controlled data from the request body using TarUtils. TarUtils is a custom library method leveraging Apache Commons Compress. During the untar process, there are no checks in place to prevent an untarred file from traversing the file system and overriding an existing file. For a successful exploitation, the attacker requires a valid __JobToken__ which may not be possible to get without using any of the other reported vulnerabilities. But this should be considered a vulnerability in `io.onedev.commons.utils.TarUtils` since it lives in a different artifact and can affect other projects using it. This issue was addressed in 4.0.3 by validating paths in tar archive to only allow them to be in specified folder when extracted.

Metrics

CVSS 3.1

8.8/10

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

EPSS Probability

12.16%

95.6th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-22

Affected Software

Vendor	Product	Versions
Onedev Project	Onedev	< 4.0.3

References

https://github.com/theonedev/onedev/security/advisories/GHSA-2w6j-wc8c-9mq2Third Party Advisory
https://github.com/theonedev/onedev/security/advisories/GHSA-2w6j-wc8c-9mq2Third Party Advisory

Timeline

Published: Jan 15, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-21251?

OneDev is an all-in-one devops platform. In OneDev before version 4.0.3 there is a critical "zip slip" vulnerability. This issue may lead to arbitrary file write. The KubernetesResource REST endpoint untars user controlled data from the request body using TarUtils. TarUtils is a custom library method leveraging Apache Commons Compress. During the untar process, there are no checks in place to prevent an untarred file from traversing the file system and overriding an existing file. For a successful exploitation, the attacker requires a valid __JobToken__ which may not be possible to get without using any of the other reported vulnerabilities. But this should be considered a vulnerability in `io.onedev.commons.utils.TarUtils` since it lives in a different artifact and can affect other projects using it. This issue was addressed in 4.0.3 by validating paths in tar archive to only allow them to be in specified folder when extracted.

How severe is CVE-2021-21251?

CVE-2021-21251 has a CVSS score of 8.8/10 (HIGH severity). The EPSS model estimates a 12.16% probability of exploitation in the next 30 days.

How do I fix CVE-2021-21251?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.