Post-Auth Unsafe Deserialization on BasePage (AJAX)

published 2021-01-15 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-8630

cvss: 9.6; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 1.5%; EPSS 1.5% chance of exploitation in 30 days, percentile 74%
public exploits: 0; none known

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.

Patch / fix

fixed in 1

onedev_project onedev 4.0.3

Exploit prediction

1.52% chance of exploitation in the next 30 days, higher than 74% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	9.6	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N
NVD	3.1	8.8	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD	2.0	6.5	AV:N/AC:L/Au:S/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

github.com /theonedev/onedev/security/advisories/GHSA-6pxf-75cf-vwjp
third-party-advisory

Sources

CVE List CVE-2021-21247
NVD CVE-2021-21247

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.

Summary