CVE-2021-21251
ZipSlip Arbitrary File Upload
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- High
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
7.7
ZipSlip Arbitrary File Upload
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.
- Record
CVE-2021-21251- CVSS 3.1
- 7.7 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:N - Weakness
- CWE-22
- Updated
- 2026-11-02
EUVDEUVD-2021-8634
7.7
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.
- Record
EUVD-2021-8634- CVSS 3.1
- 7.7 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:N - Updated
- 2026-11-03
NVD
7.7
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.
- Record
CVE-2021-21251- CVSS 3.1
- 7.7 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:N - CVSS 3.1
- 8.8 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - CVSS 2.0
- 6.5 Medium
AV:N/AC:L/Au:S/C:P/I:P/A:P - Weakness
- CWE-22
- Updated
- 2026-11-02
OSV
8.8
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.
- Record
CVE-2021-21251- CVSS 3.1
- 8.8 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-21251 is a high vulnerability (CVSS 7.7) in Onedev Project Onedev, published January 15, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 12.7%, the 96th percentile. No source names a fixed version.