CVE-2021-39195

Name: CVE-2021-39195
Creator: NVD / NIST
Published: 2021-09-07T19:15:08.6+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.5/10EPSS 1.03%

Last modified Jun 17, 2026

CVE-2021-39195 is a medium-severity vulnerability rated 6.5/10 on the CVSS scale. 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. EPSS estimates a 1.03% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1

6.5/10

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

EPSS Probability

1.03%

59.3th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-918

Affected Software

Vendor	Product	Versions
Misskey	Misskey	< 12.90.0

References

https://github.com/misskey-dev/misskey/blob/develop/CHANGELOG.md#12900-20210904Release Notes, Third Party Advisory
https://github.com/misskey-dev/misskey/commit/e1a8b158e04ad567d92d8daf3cc0898ee18f1a2ePatch, Third Party Advisory
https://github.com/misskey-dev/misskey/security/advisories/GHSA-mqv7-gxh4-r5vfIssue Tracking, Patch, Third Party Advisory
https://github.com/misskey-dev/misskey/blob/develop/CHANGELOG.md#12900-20210904Release Notes, Third Party Advisory
https://github.com/misskey-dev/misskey/commit/e1a8b158e04ad567d92d8daf3cc0898ee18f1a2ePatch, Third Party Advisory
https://github.com/misskey-dev/misskey/security/advisories/GHSA-mqv7-gxh4-r5vfIssue Tracking, Patch, Third Party Advisory

Timeline

Published: Sep 7, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-39195?

How severe is CVE-2021-39195?

CVE-2021-39195 has a CVSS score of 6.5/10 (MEDIUM severity). The EPSS model estimates a 1.03% probability of exploitation in the next 30 days.

How do I fix CVE-2021-39195?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-39195?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST