PatchSiren cyber security CVE debrief
CVE-2026-57575 misskey-dev CVE debrief
CVE-2026-57575 is a Server-Side Request Forgery (SSRF) vulnerability in Misskey's URL preview functionality. The issue allows a remote attacker to cause the Misskey server to initiate HTTP requests to loopback, private, or link-local services due to missing network restrictions before establishing outbound connections. However, no sensitive internal data is believed to be transmitted back or exposed to the attacker as IP address validation takes place after the request has been sent and the process is subsequently rejected. This issue is fixed in version 2026.6.0.
- Vendor
- misskey-dev
- Product
- misskey
- CVSS
- MEDIUM 6.9
- CISA KEV
- Not listed in stored evidence
- Original CVE published
- 2026-07-10
- Original CVE updated
- 2026-07-10
- Advisory published
- 2026-07-10
- Advisory updated
- 2026-07-10
Who should care
Administrators and users of Misskey social media platform should be aware of this SSRF vulnerability. They should ensure that their Misskey instance is updated to version 2026.6.0 or later to prevent potential exploitation.
Technical summary
The vulnerability exists in the UrlPreviewService of Misskey, allowing an attacker to forge requests to internal or private services. The issue arises from the lack of network restrictions before establishing outbound connections. Although the process is rejected after sending the request due to IP address validation, the vulnerability still poses a risk. The fix in version 2026.6.0 addresses this issue by implementing necessary restrictions.
Defensive priority
Medium priority should be given to updating Misskey instances to version 2026.6.0 or later. Monitoring for potential exploitation attempts and ensuring proper network configurations can also help mitigate the risk.
Recommended defensive actions
- Update Misskey to version 2026.6.0 or later
- Monitor for potential exploitation attempts
- Ensure proper network configurations to restrict outbound connections
- Review compensating controls for exposed systems while remediation is scheduled and verified
- Check relevant monitoring, detection, and logs for exposed assets that need extra review
- Track exceptions, retest remediated assets, and close the item only after evidence is documented
- Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up
Evidence notes
The CVE record and NVD detail provide information about the vulnerability. The source references include commits and release notes from the Misskey project, confirming the fix in version 2026.6.0. Evidence is limited to public statements from the vendor and CVE details. Defenders should verify the update status of their Misskey instances and review network configurations for potential exposure. They should also monitor for exploitation attempts and implement compensating controls if immediate patching is not feasible.
Official resources
AI-assisted PatchSiren debrief based on the supplied source corpus. The CVE record was published on 2026-07-10T21:16:59.820Z and has not been modified since then.