CVE-2021-39195 Server-Side Request Forgery vulnerability in misskey

High 7.7 Published 7 Sep 2021 Updated 4 Aug 2024

Attackers can exploit Server-Side Request Forgery in Misskey to disclose non-public information from the internal network.

Exploited in the wild: Not known
Login needed: Any signed-in user
Attackable: Over the internet
Victim action needed: Not needed
Fix: None listed

What is CVE-2021-39195?

CVE-2021-39195 is a high-severity server-side request forgery vulnerability in misskey-dev misskey, published on 7 Sep 2021. Any signed-in user can exploit it over the network, with no action from the victim.

Official description

Misskey is an open source, decentralized microblogging platform. In affected versions a Server-Side Request Forgery vulnerability exists in "Upload from URL" and remote attachment handling. This could result in the disclosure of non-public information within the internal network. This has been fixed in 12.90.0. However, if you are using a proxy, you will need to take additional measures. As a workaround this exploit may be avoided by appropriately restricting access to private networks from the host where the application is running.

Weakness: CWE-918

Which versions are affected by CVE-2021-39195?

It affects 1 product.

Products include Misskey Misskey.

How do I fix CVE-2021-39195?

No fix has been published for CVE-2021-39195 yet. Limit exposure of the affected software until one is available.

Upgrade, and send outbound requests through an allow-list that blocks internal addresses. More about Server-side request forgery.

Is CVE-2021-39195 being exploited?

There is no known exploitation of CVE-2021-39195 in the wild and no public exploit code.

Sources

Also known as GHSA-mqv7-gxh4-r5vf.