CVEvulnerability

CVE-2021-21249

8.8 HIGH Published 2021-01-15 Modified 2026-06-17 Official page ↗
Status
Modified
Published
2021-01-15
Last modified
2026-06-17
Assigner
[email protected]
CVSS 3.1 ([email protected])
9.6 CRITICAL — CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N
CVSS 3.1 ([email protected])
8.8 HIGH — CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CVSS 2.0 ([email protected])
6.5 MEDIUM — AV:N/AC:L/Au:S/C:P/I:P/A:P
Weaknesses
CWE-502, CWE-74

Description

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

Affected configurations

• onedev project onedev (< 4.0.3)

Related

Weakness · CWE (2)

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

References