Cyber Resilience

CVE-2021-39195

High

Published: 07 September 2021

Published
07 September 2021
Modified
21 November 2024
KEV Added
Patch
CVSS Score v3.1 7.7 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N
EPSS Score 0.0024 47.3th percentile
Risk Priority 16 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2021-39195 is a high-severity SSRF (CWE-918) vulnerability in Misskey Misskey. Its CVSS base score is 7.7 (High).

Operationally, ranked at the 47.3th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

EU & UK References

Vulnerability details

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…

more

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.

CWE(s)

Related Threats

No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.

Affected Assets

misskey
misskey
≤ 12.90.0

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-918

Penetration testing attempts server-side requests to internal resources, identifying SSRF weaknesses for remediation.

addresses: CWE-918

Outbound connections to external resources can be monitored and limited at the boundary, reducing SSRF impact.

addresses: CWE-918

Validates server-side URLs and resource references to block SSRF attempts.

addresses: CWE-918

Detects server-side request forgery through monitoring of unexpected outbound connections.

References