CVE-2026-100635

Medium

Description

SiYuan before v3.8.4 contains an authentication bypass vulnerability in the publish service where session cookies are issued without Secure or SameSite attributes over plaintext HTTP connections. An on-path attacker can observe a valid publish-visitor-session-id cookie from a Basic Auth exchange and replay it to access authenticated publish endpoints without knowing the account password.

SeverityMedium

CVSS5.9

Exploit probability—

ProductSiyuan

PublishedSep 26, 2026

First seenSep 26, 2026

Weakness typeCWE-319CWE-319

How to fix

Update

siyuan-note siyuan3.8.4 or later

Patches

Vendor advisories

github.com/siyuan-note/siyuan/security/advisories/GHSA-7j37-4gq6-wm7m

Affected products

Product	Affected versions	Fixed in
siyuan-note siyuan	v < 3.8.4	3.8.4

Check your version

Choose the product and enter the version you run to see whether it falls in the affected range.

In the Intelligence 360 plan

Attack Surface Management

See the assets tied to your domains, the technologies they run and known vulnerabilities in one list.