TI-2026-80184 Aliases CVE-2026-116166 GHSA-89mj-v839-4h76

Cleartext transmission in SiYuan exposes login and session cookies

HIGH 68CWE-319Published 2026-10-25 · Updated 2026-10-29

Key facts

Attack vector: Adjacent network
Privileges required: None
User interaction: None
Attack complexity: High
Attack requirements: Present
Impact type: Information disclosure
Confidentiality · integrity · availability: High · High · None
Fix status: Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-319.

Summary

SiYuan from 3.6.0 before 3.8.7 accepts and saves the networkServeTLS setting but never enforces it, so the kernel port keeps serving full API access over plain HTTP alongside HTTPS. A network-adjacent attacker can sniff the cleartext login flow and session cookie, which lacks the Secure attribute, to hijack kernel API sessions. The flaw is tracked as CWE-319, cleartext transmission of sensitive information.

Written with Claude Haiku 5.5 from the sources below · 2026-10-29

Description from the CNA

SiYuan 3.6.0 before 3.8.7 accepts and persists the networkServeTLS setting but never enforces it, so the kernel port keeps serving full API access over plain HTTP alongside HTTPS. Network-adjacent attackers can sniff the cleartext login flow and session cookie, which lacks the Secure attribute while responses omit HSTS, to hijack kernel API sessions.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV

EPSS 0.00115 1st percentileScored 2026-11-07

Fix Fixed siyuan (siyuan-note): 3.8.7

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: Poc
Automatable: No
Technical impact: Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
siyuan-note	siyuan	3.6.0 to before 3.8.7	3.8.7	Patch available	CNA

siyuan Vendorsiyuan-note Affected 3.6.0 to before 3.8.7 Fixed in 3.8.7 Patch available CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPE	Versions	Role	Vendor
cpe:2.3:a:b3log:siyuan::::::::	—	—	siyuan-note

cpe:2.3:a:b3log:siyuan:*:*:*:*:*:*:*:* Versions — — ·siyuan-note

Remediation

Update SiYuan to version 3.8.7 or later, which fixes the issue.

Written with Claude Haiku 5.5 from the sources below · 2026-10-29

Fix · CNA siyuan (siyuan-note) Fixed in 3.8.7

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

Release · 2026-10-25
siyuan-note siyuan 3.8.7
6 records Highest priority Priority HIGH 1 HIGH, 3 MEDIUM, 2 LOW
Other records, highest priority first
- TI-2026-80188 SQL injection in SiYuan history search exposes history.dbPriority MEDIUM 64
- TI-2026-80186 Path traversal in SiYuan MCP asset tool lets attackers read local filesPriority MEDIUM 64
- TI-2026-80187 SiYuan Stored XSS via KaTeX \href in Math BlocksPriority MEDIUM 56
Show all 6 records →

Timeline

2026-10-25 Threatist record created from CVE-2026-116166
2026-10-26 Priority changed: MEDIUM → LOW
2026-10-27 Alias added: GHSA-89mj-v839-4h76
2026-10-29 CISA SSVC decision points changed
2026-10-29 Priority changed: LOW → HIGH

References

Advisory 1

GitHub Security Advisory (GHSA-hpj5-f7cj-vvwr)

TI-2026-48492 SiYuan before v3.7.3 SQL Injection via searchDocs CVSS 4.0CRITICAL 9.9
TI-2026-48491 SiYuan before v3.7.3 SQL Injection via searchEmbedBlock CVSS 4.0CRITICAL 9.9
TI-2026-48490 SiYuan before v3.7.3 SQL Injection via fullTextSearchAssetContent CVSS 4.0CRITICAL 9.9
TI-2026-47010 SiYuan before v3.7.2 Unauthenticated Administrator Takeover via MCP CVSS 4.0CRITICAL 10.0
TI-2026-26050 SiYuan has directory traversal within its publishing service CVSS 3.1CRITICAL 9.8
TI-2026-25256 SiYuan: Authorization Bypass Allows Arbitrary SQL Execution via Search API CVSS 3.1CRITICAL 9.8

See all 242 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences