SEPTEMBER 19, 2026
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Case File

CVE-2026-74905

HIGH · CVSS 7.1 EPSS 0.32% Public Exploit

Source: NVD + CISA KEV + EPSS · Published 2026-08-18 · Last synced 2026-09-17

CyberRota Analysis

AI-Generated

The vulnerability affects SiYuan versions prior to 3.7.4, specifically in the isPrivateIP function, which fails to properly validate certain IPv6 transition addresses, allowing authenticated attackers to exploit SSRF protections. This can lead to unauthorized access to internal services and sensitive cloud metadata, enabling attackers to steal instance credentials and conduct internal reconnaissance. Organizations using SiYuan should prioritize patching this vulnerability to mitigate the risk of data breaches and unauthorized access to critical infrastructure.

Public Exploit Signal

A public exploit, PoC, GitHub repository or Metasploit reference was detected for this CVE.

GitHub PoC Links

Note: these links are listed for security research and verification purposes only.

CVE
CVE-2026-74905
Severity
HIGH
CVSS
7.1
EPSS
0.32%

Original NVD Description

SiYuan before v3.7.4 contains a server-side request forgery (SSRF) vulnerability in the isPrivateIP function in kernel/util/net.go, used by SSRFSafeDialer to enforce SSRF protection in SafeMode. The function only checks for loopback, link-local unicast, private, and unspecified addresses and does not recognize IPv6 transition addresses (NAT64 64:ff9b::/96, 6to4 2002::/16, Teredo 2001::/32) that embed private IPv4 destinations. When SafeMode is enabled, an authenticated attacker can bypass the SSRF guard via the network forward proxy, WebSocket proxy, or SSE proxy endpoints by supplying a URL whose hostname resolves to such a transition address, reaching internal services and cloud metadata endpoints (e.g., 169.254.169.254). Because the forward proxy returns the full response body, this is a full-read SSRF that can be used to steal instance credentials, reach internal services, and port-scan internal infrastructure.