CVE-2021-21249
Post-Auth Unsafe Yaml deserialization
- State
- Published
- Severity
- 9.6 Critical
- Published
- Jan 15, 2021
- Updated
- Aug 3, 2024
- Reserved
- Dec 22, 2020
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
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 9.6 Critical | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N | GitHub_M |
Weaknesses
- CWE-74 Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')
Affected Products
| Product | Versions |
|---|---|
onedevtheonedev |
|
References
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