CVE-2026-57575: CWE-918: Server-Side Request Forgery (SSRF) in misskey-dev misskey
Misskey is an open source, federated social media platform. Prior to 2026.6.0, Misskey contains a Server-Side Request Forgery (SSRF) vulnerability in URL preview functionality in UrlPreviewService. Due to missing network restrictions before establishing outbound connections, a remote attacker can cause the Misskey server to initiate HTTP requests to loopback, private, or link-local services. Because IP address validation takes place after the request has been sent and the process is subsequently rejected, no sensitive internal data is believed to be transmitted back or exposed to the attacker. This issue is fixed in version 2026.6.0.
AI Analysis
Technical Summary
CVE-2026-57575 is a Server-Side Request Forgery (SSRF) vulnerability in Misskey's UrlPreviewService affecting versions before 2026.6.0. The vulnerability allows remote attackers to cause the server to initiate HTTP requests to loopback, private, or link-local addresses due to missing network restrictions prior to connection establishment. The IP address validation happens post-request, which rejects the connection but does not prevent the initial request from being sent. No sensitive internal data leakage is confirmed. The vulnerability is fixed in version 2026.6.0.
Potential Impact
An attacker can induce the Misskey server to send HTTP requests to internal network resources, potentially enabling reconnaissance or interaction with internal services not directly accessible externally. However, because the server validates IP addresses after sending the request and rejects the connection, no sensitive internal data is believed to be disclosed to the attacker. The impact is limited to the ability to make outbound requests to internal addresses without data exposure.
Mitigation Recommendations
Upgrade Misskey to version 2026.6.0 or later, where this SSRF vulnerability is fixed. No other mitigation is indicated or necessary as the issue is resolved in this official release.
CVE-2026-57575: CWE-918: Server-Side Request Forgery (SSRF) in misskey-dev misskey
Description
Misskey is an open source, federated social media platform. Prior to 2026.6.0, Misskey contains a Server-Side Request Forgery (SSRF) vulnerability in URL preview functionality in UrlPreviewService. Due to missing network restrictions before establishing outbound connections, a remote attacker can cause the Misskey server to initiate HTTP requests to loopback, private, or link-local services. Because IP address validation takes place after the request has been sent and the process is subsequently rejected, no sensitive internal data is believed to be transmitted back or exposed to the attacker. This issue is fixed in version 2026.6.0.
CVSS v4.0
Score 6.9medium
Affected software
pkg:github/misskey-dev/misskeyRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-57575 is a Server-Side Request Forgery (SSRF) vulnerability in Misskey's UrlPreviewService affecting versions before 2026.6.0. The vulnerability allows remote attackers to cause the server to initiate HTTP requests to loopback, private, or link-local addresses due to missing network restrictions prior to connection establishment. The IP address validation happens post-request, which rejects the connection but does not prevent the initial request from being sent. No sensitive internal data leakage is confirmed. The vulnerability is fixed in version 2026.6.0.
Potential Impact
An attacker can induce the Misskey server to send HTTP requests to internal network resources, potentially enabling reconnaissance or interaction with internal services not directly accessible externally. However, because the server validates IP addresses after sending the request and rejects the connection, no sensitive internal data is believed to be disclosed to the attacker. The impact is limited to the ability to make outbound requests to internal addresses without data exposure.
Mitigation Recommendations
Upgrade Misskey to version 2026.6.0 or later, where this SSRF vulnerability is fixed. No other mitigation is indicated or necessary as the issue is resolved in this official release.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-06-24T18:49:56.208Z
- Cvss Version
- 4.0
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a515e2368715ace43325a1d
Added to database: 07/10/2026, 21:03:31 UTC
Last enriched: 07/18/2026, 15:14:28 UTC
Last updated: 08/24/2026, 22:52:12 UTC
Views: 85
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