CVE-2021-21251
No exploitation reported by the sources we read.
- Published2021-01-15
- Fixed in4.0.3
- WeaknessCWE-22
Am I affected?
Debian, Ubuntu or Red Hat sometimes backport a fix without changing the upstream version number: such a version reads « to verify », never « affected ».With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.
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.
Timeline
dates in UTC- 2021-01-1521:15CVE publishedNVD
- 2026-10-2319:23EPSS crossed 10 %FIRST EPSS
Observed activity
isMalicious corpus · updated 2026-10-23 18:48 UTCBlock these indicators
- Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2021-21251?format=txt
- CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-21251?format=csv
- TAXII collection of exploited CVEs
- The EDL and CSV take an API key on the Pro plan.
Versions per branch
NVD| Branch | Affected | Fixed in | Source |
|---|---|---|---|
| 4.0 | < 4.0.3 | 4.0.3 | NVD |
as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.
Fix
- Update Onedev project onedev to 4.0.3
Detection
- Nuclei template
- none so far ProjectDiscovery
- Exploit-DB
- no entry Exploit-DB
- Proof-of-concept repositories
- none listed PoC-in-GitHub
Sources
- CNACVSS 3.17.7read 2026-10-23
- NVDCVSS 3.18.8read 2026-10-23
- NVDCVSS 2.06.5read 2026-10-23
- CNAweakness (CWE)CWE-22read 2026-10-23
- FIRST EPSSEPSS score12.7 %read 2026-10-23
Technical details
- CVSS v3 Vector
- CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Published
- 2021-01-15
- Last Modified
- 2026-06-17
- NVD status
- Modified
Frequently asked questions
What is CVE-2021-21251?
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