CVE-2026-100635: siyuan · Cleartext Transmission
Affects siyuanSource CVE Database V5
Not known to be exploited · CVSS 8.2 High : upgrade to 3.8.4 soon.
Data as of 8 Nov 2026, 23:24 UTC
Thin evidence
One scorer or none| CNA (VulnCheck) | CVSS 4.0 | 8.2 |
|---|---|---|
| CNA (VulnCheck) | CVSS 3.1 | 5.9 |
- EPSS
- 0.3% chance of exploitation in 30 days – higher than 25% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 3.8.4
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 26 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 9 Nov 2026.
What to do
Upgrade siyuan and siyuan-note/siyuan to 3.8.4.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| siyuan-notesiyuan | Affected
| Fixed in
|
GitHubsiyuan-note/siyuanpkg:github/siyuan-note/siyuanOther threats | Affected
| Fixed in
|
Gosiyuanpkg:golang/siyuanOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
Upgrade SiYuan to version 3.8.4 or later, where this vulnerability is fixed. The fix addresses the insecure transmission of session cookies by enforcing Secure and SameSite attributes and presumably using encrypted connections. No other mitigation is indicated.
Description
SiYuan versions prior to 3.8.4 have an authentication bypass vulnerability in the publish service. Session cookies are transmitted without Secure or SameSite attributes over plaintext HTTP, allowing an attacker on the network path to capture and replay a valid session cookie to access authenticated publish endpoints without the account password. This issue is fixed in version 3.8.4.
References
- github.com/siyuan-note/siyuan/security/advisories/GHSA-7j37-4gq6-wm7m (opens in a new tab)
- github.com/siyuan-note/siyuan/commit/79d47867b106467c951475a9193455b48d1f3682 (opens in a new tab)
- github.com/siyuan-note/siyuan/commit/ff4d215f78a8d6e6db6052be18b5f9f4db9c7d68 (opens in a new tab)
- vulncheck.com/advisories/siyuan-before-3.8.4-authentication-bypass-via-plaintext-session-cookie (opens in a new tab)