CVE-2021-32824
Apache Dubbo vulnerable to remote code execution via Telnet Handler
Description
Apache Dubbo is a Java based, open source RPC framework. Versions prior to 2.6.10 and 2.7.10 are vulnerable to pre-authorization remote code execution via arbitrary bean manipulation in the Telnet handler. The Dubbo main service port can be used to access a Telnet Handler which offers some basic methods to collect information about the providers and methods exposed by the service and it can even allow to shutdown the service. This endpoint is unprotected. Additionally, a provider method can be invoked using the `invoke` handler. This handler uses a safe version of FastJson to process the call arguments. However, the resulting list is later processed with `PojoUtils.realize` which can be used to instantiate arbitrary classes and invoke its setters. Even though FastJson is properly protected with a default blocklist, `PojoUtils.realize` is not, and an attacker can leverage that to achieve remote code execution. Versions 2.6.10 and 2.7.10 contain fixes for this issue.
How to fix CVE-2021-32824
To remediate CVE-2021-32824, upgrade the affected package to a fixed version below.
- —upgrade to 2.6.10 or later
Is CVE-2021-32824 being exploited?
Moderate — EPSS is 5.9%. Track this CVE but it's not at the top of the prioritisation list.
Affected packages (1)
- from 0, < 2.6.10
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | CRITICAL9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |