TI-2021-16580 Aliases CVE-2021-39195

Server-Side Request Forgery vulnerability in misskey

LOW 36CWE-918Published 2021-09-07 · Updated 2024-08-04

Key facts

Attack vector: Network
Privileges required: Low
User interaction: None
Attack complexity: Low
Impact type: Information disclosure
Confidentiality · integrity · availability: High · None · None
Fix status: Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-918 and the CVSS impact.

Summary

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.

Why it matters now

EPSS 0.01062 64th percentileScored 2026-11-07

Fix Fixed misskey (misskey-dev): 12.90.0

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
misskey-dev	misskey	before 12.90.0	12.90.0	Patch available	CNA

misskey Vendormisskey-dev Affected before 12.90.0 Fixed in 12.90.0 Patch available CNA

CPE configurations NVD · 1

CPE	Versions	Role	Vendor
cpe:2.3:a:misskey:misskey::::::::	before 12.90.0	Vulnerable	misskey-dev

cpe:2.3:a:misskey:misskey:*:*:*:*:*:*:*:* Versions before 12.90.0 Vulnerable ·misskey-dev

Remediation

Fix · CNA misskey (misskey-dev) Fixed in 12.90.0

Timeline

2026-10-02 Threatist record created from CVE-2021-39195

References

Patch 2

Advisory 1

https://github.com/misskey-dev/misskey/blob/develop/CHANGELOG.md#12900-20210904

TI-2025-18599 Misskey CSRF vulnerability due to insecure configuration of authentication cookie attributes CVSS 3.1HIGH 8.2
TI-2025-29081 Misskey CSS Style Injection Vulnerability In `MkUrlPreview` CVSS 3.1HIGH 7.2
TI-2025-40906 Misskey has a login rate limit bypass via spoofed X-Forwarded-For header CVSS 4.0MEDIUM 6.9
TI-2025-29276 Misskey Directory Traversal Vulnerability in AiScript via `Mk:api` CVSS 3.1HIGH 7.5
TI-2025-40839 misskey.js's export data contains private post data CVSS 4.0HIGH 7.1
TI-2026-22705 Misskey lacks proper authorization checks and input validation CVSS 4.0CRITICAL 9.2

See all 26 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences