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CVE-2021-21251

HighCVSS 8.8 / 10
Published Jan 15, 2021·Last modified Apr 10, 2026
Affected Components(0)

No affected components available

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.

Risk Scores
Base Score
8.8

The vulnerability can be exploited over the network without needing physical access. It is easy for an attacker to exploit this vulnerability. An attacker needs basic access or low-level privileges. No user interaction is needed for the attacker to exploit this vulnerability. The impact is confined to the system where the vulnerability exists. There is a high impact on the confidentiality of the information. There is a high impact on the integrity of the data. There is a high impact on the availability of the system.

Threat Intelligence
8.1

Exploitation activity has been observed. Apply available patches or mitigations urgently.

EPSS
12.16%

The exploit probability is low. The vulnerability is unlikely to be exploited in the next 30 days.

Exploit
Not available

We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.

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