Vulnerability Monitor

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CVE-2021-39195


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.


Security Impact Summary

This vulnerability carries a HIGH severity rating with a CVSS v3.1 score of 7.7, indicating it can be exploited remotely over the network with relatively low complexity without requiring user interaction requiring only low-level privileges . The vulnerability impacts confidentiality (data exposure), for affected systems. Impacting 1 product from misskey organizations running these solutions should prioritize assessment and patching.

Historical Context

Reported in 2021, this vulnerability emerged during an era marked by increased sophistication in supply chain attacks, cloud infrastructure vulnerabilities, and software-as-a-service (SaaS) security challenges. Security practices during this period emphasized zero-trust architectures, container security, and API protection.


Published

2021-09-07T19:15:08.600

Last Modified

2024-11-21T06:18:51.590

Status

Modified

Source

[email protected]

Severity

CVSSv3.1: 7.7 (HIGH)

CVSSv2 Vector

AV:N/AC:L/Au:S/C:P/I:N/A:N

  • Access Vector: NETWORK
  • Access Complexity: LOW
  • Authentication: SINGLE
  • Confidentiality Impact: PARTIAL
  • Integrity Impact: NONE
  • Availability Impact: NONE
Exploitability Score

8.0

Impact Score

2.9

Weaknesses
  • Type: Secondary
    CWE-918

Affected Vendors & Products
Type Vendor Product Version/Range Vulnerable?
Application misskey misskey < 12.90.0 Yes

References

How SecUtils Interprets This CVE

SecUtils normalizes and enriches National Vulnerability Database (NVD) records by standardizing vendor and product identifiers, aggregating vulnerability metadata from both NVD and MITRE sources, and providing structured context for security teams. For misskey's affected products, we extract Common Platform Enumeration (CPE) data, Common Weakness Enumeration (CWE) classifications, CVSS severity metrics, and reference data to enable rapid vulnerability prioritization and asset correlation. This record contains no exploit code, proof-of-concept instructions, or attack methodologies—only defensive intelligence necessary for patch management, risk assessment, and security operations.