CVE-2021-21249

mediumpriority · track · 36EPSS 0.031 · 88 %ileEUUS

grimoire priorityP3 · Track

Exploitable?

—

no known exploitation

Likely / severe?

3.06% (88th) EPSS

CVSS 6.5 · medium

Is it mine?

2 products

Check your exposure

Who says so?

3 sources

cnnvd · enisa_euvd · nvd

EPSS · scored 2026-10-22

OneDev is an all-in-one devops platform. In OneDev before version 4.0.3, there is an issue involving YAML parsing which can lead to post-auth remote code execution. In order to parse and process YAML files, OneDev uses SnakeYaml which by default (when not using `SafeConstructor`) allows the instantiation of arbitrary classes. We can leverage that to run arbitrary code by instantiating classes such as `javax.script.ScriptEngineManager` and using `URLClassLoader` to load the script engine provider, resulting in the instantiation of a user controlled class. For a full example refer to the referenced GHSA. This issue was addressed in 4.0.3 by only allowing certain known classes to be deserialized

cvss

Technical severity, 0–10. One row per scoring source.

9.6

010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–critical · 6.5–9.6

v2.06.5mediumAV:N/AC:L/Au:S/C:P/I:P/A:Pprimary · NVD / NIST USexploitability 8 · impact 6.4

v3.18.8highCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:Hprimary · NVD / NIST USexploitability 2.8 · impact 5.9

v3.19.6criticalCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:Nsecondary · ENISA EU

v3.19.6criticalCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:Nsecondary · security-advisories@github.comexploitability 3.1 · impact 5.8

v3.18.1highCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:Usecondary · CVSS-BT (t0sche)

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-502USprimaryCWE-74US

affected products (2)

Products and version ranges known to be affected.

theonedev onedev≤ < 4.0.3enisa_euvdEU
onedev project onedev< 4.0.3nvdUScpe:2.3:a:onedev_project:onedev:*:*:*:*:*:*:*:*

also known as (2)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd nvd NVD CVE.org MITRE

published 2021-01-15modified 2026-06-17

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+3688 more

references (7)

External citations — patches, advisories, analysis.

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