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No exploitation reportedFix available

CVE-2021-21247

No exploitation reported by the sources we read.

  • Published2021-01-15
  • Fixed in4.0.3
  • WeaknessCWE-502 · CWE-74

Am I 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, the application's BasePage registers an AJAX event listener (`AbstractPostAjaxBehavior`) in all pages other than the login page. This listener decodes and deserializes the `data` query parameter. We can access this listener by submitting a POST request to any page. This issue may lead to `post-auth RCE` This endpoint is subject to authentication and, therefore, requires a valid user to carry on the attack. This issue was addressed in 4.0.3 by encrypting serialization payload with secrets only known to server.

Timeline

dates in UTC
  1. 2021-01-1521:15CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 18:48 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2021-21247?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-21247?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD
Onedev project onedev
BranchAffectedFixed in
4.0< 4.0.34.0.3

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

  1. 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 3.19.6read 2026-10-23
  • NVDCVSS 3.18.8read 2026-10-23
  • NVDCVSS 2.06.5read 2026-10-23
  • CNAweakness (CWE)CWE-74read 2026-10-23
  • NVDweakness (CWE)CWE-502read 2026-10-23
  • FIRST EPSSEPSS score1.5 %2026-10-22

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-2021-21247?

OneDev is an all-in-one devops platform. In OneDev before version 4.0.3, the application's BasePage registers an AJAX event listener (`AbstractPostAjaxBehavior`) in all pages other than the login page. This listener decodes and deserializes the `data` query parameter. We can access this listener by submitting a POST request to any page. This issue may lead to `post-auth RCE` This endpoint is subject to authentication and, therefore, requires a valid user to carry on the attack. This issue was addressed in 4.0.3 by encrypting serialization payload with secrets only known to server.

Is CVE-2021-21247 actively exploited?

Active exploitation of CVE-2021-21247 has not been confirmed. Its EPSS score was 1.5% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-21247?

CVE-2021-21247 has a CVSS v3 base score of 8.8 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

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