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Fencer Vulns
critical 10.0

CVE-2021-21242 in the critical feed json

Pre-Auth Unsafe Deserialization on AttachmentUploadServet

published 2021-01-15 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-8625

cvss
10.0
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
74.2%
EPSS 74.2% chance of exploitation in 30 days, percentile 99.4%
public exploits
0
none known

Summary

OneDev is an all-in-one devops platform. In OneDev before version 4.0.3, there is a critical vulnerability which can lead to pre-auth remote code execution. AttachmentUploadServlet deserializes untrusted data from the `Attachment-Support` header. This Servlet does not enforce any authentication or authorization checks. This issue may lead to pre-auth remote code execution. This issue was fixed in 4.0.3 by removing AttachmentUploadServlet and not using deserialization

Patch / fix

  • onedev_project onedev 4.0.3

Exploit prediction

74.19% chance of exploitation in the next 30 days, higher than 99.4% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 10.0 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N
NVD 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 7.5 AV:N/AC:L/Au:N/C:P/I:P/A:P

Affected products

  • theonedev onedev

Classification

Weakness
  • CWE-74 Improper Neutralization of Special Elements in Output Used by a Downstream Component
  • CWE-502 Deserialization of Untrusted Data

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.