CVE-2026-100635

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.

CVSS 4.0

8.2CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N

CVSS 3.1

5.9CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

EPSS

0.3% chance of exploitation in the next 30 days; higher than 25% of CVEs (scores of 2026-10-25)

CWE

CWE-319

Published

2026-09-26

Modified

2026-10-08

Record from

the NVD, synced 2026-10-19

References

• https://github.com/siyuan-note/siyuan/commit/79d47867b106467c951475a9193455b48d1f3682
• https://github.com/siyuan-note/siyuan/commit/ff4d215f78a8d6e6db6052be18b5f9f4db9c7d68
• https://github.com/siyuan-note/siyuan/security/advisories/GHSA-7j37-4gq6-wm7m
• https://www.vulncheck.com/advisories/siyuan-before-3.8.4-authentication-bypass-via-plaintext-session-cookie
• https://github.com/siyuan-note/siyuan/security/advisories/GHSA-7j37-4gq6-wm7m

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