SB2026070303 - Multiple vulnerabilities in Misskey

Description

This security bulletin contains information about 2 vulnerabilities.

1) Server-Side Request Forgery (SSRF) (CVE-ID: CVE-2026-57575)

CWE-ID: CWE-918 - Server-Side Request Forgery (SSRF)

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Green

The disclosed vulnerability allows a remote attacker to perform SSRF attacks.

The vulnerability exists due to insufficient validation of user-supplied input in the URL preview functionality. A remote attacker can send a specially crafted HTTP request and trick the application to initiate requests to arbitrary systems.

Successful exploitation of this vulnerability may allow a remote attacker gain access to sensitive data, located in the local network or send malicious requests to other servers from the vulnerable system.

2) Authentication Bypass by Capture-replay (CVE-ID: CVE-2026-57574)

CWE-ID: CWE-294 - Authentication Bypass by Capture-replay

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:U/U:Amber

The vulnerability allows a remote attacker to bypass authentication process.

The vulnerability exists due to an error in Time-based One-Time Password (TOTP) authentication. A remote attacker can reuse the code to perform unauthorized actions.

Remediation

Install update from vendor's website.

References

• https://github.com/misskey-dev/misskey/security/advisories/GHSA-jvcx-f39m-5xrj
• https://github.com/misskey-dev/misskey/security/advisories/GHSA-2m5x-5mp6-6vpq