CVE.org (no NVD analysis yet)· CNA VulnCheck

CVE-2026-116171: SiYuan 3.5.4 before 3.8.7 Sensitive Path Bypass via Windows Extended-Length Prefix

MediumCVSS 5.9 · v4.0—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 23/100)

The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
Probability of exploitation in the next 30 days: 0.47% (FIRST EPSS).
Anyone who can reach it over the internet can trigger it. Administrator privileges are required. No user action is required. No special conditions are required; it is repeatable.
According to CISA the attack is automatable: targets can be found by mass scanning.
Fixed version: siyuan-note siyuan 3.8.7.

Low priority for now. Upgrade to siyuan-note siyuan 3.8.7 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

SiYuan 3.5.4 before 3.8.7 on Windows contains a sensitive-path denylist bypass in IsSensitivePath because the Windows extended-length prefix (\\?\) survives filepath.Clean and matches no forbidden prefix. Authenticated API callers can prepend the prefix to localPath in /api/import/importStdMd to copy workspace conf files, including the API token and TLS private keys, into assets served to unauthenticated clients.

Path traversal

EUVD-2026-109432

Published: Oct 25, 2026
Updated: Oct 28, 2026
EPSS: 0.4% · 41th percentile
CWE: CWE-22

Report tools

JSON

Action score

Monitor

Low priority for now.

CVSS: 23 / 40 · 5.9 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.4%

CISA SSVC decision

Exploitation: none
Automatable: yes
Technical impact: partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD: —
CNA · VulnCheck: 5.9; NVD has not scored this yet; the score shown is the CNA’s.

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

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

Not in KEV: no record of exploitation in the wild
No public exploit code on record
A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Is your version affected? Check it

Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

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Versions reported by the vendor

Affected version ranges reported by the assigning authority (VulnCheck). Independent of NVD's CPE analysis and usually ahead of it.

siyuan-note siyuan
- 3.8.7not affected
- 3.5.4 and later · before 3.8.7affected · semver

Same product

siyuan-note: all records

Other highest-scoring records for the same primary product.

CVE-2026-66012SiYuan before v3.7.2 Unauthenticated Administrator Takeover via MCP
40Plan
CVE-2026-72811SiYuan before v3.7.4 SQL Injection via backlink search
39Monitor
CVE-2026-69085SiYuan before v3.7.3 SQL Injection via searchDocs
39Monitor

Published before and after this one in the same product

← EarlierCVE-2026-116169Oct 25, 2026 · SiYuan 2.10.0 before 3.8.7 Stored XSS via KaTeX \href in Math Blocks
20Monitor
← EarlierCVE-2026-116170Oct 25, 2026 · SiYuan before v3.8.7 SQL Injection via History Search op and query
27Monitor
Later →CVE-2026-118680Oct 28, 2026 · SiYuan 3.8.7 through 3.8.8 Path Traversal via GLOBALROOT Alias
23Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / package	Fixed version	Source
siyuan-note siyuan	3.8.7	Vendor (CNA)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

PublishedOct 25, 2026
Fix recordedOct 25, 2026same day
TodayNov 13, 2026+19 d

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

Hama1ccoreporter

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

CVE-2026-7708665 days apartSiYuan before v3.7.4 Path Traversal via packageName
37Monitor
CVE-2026-7479869 days apartSiYuan kernel Path Traversal via database_clean MCP tool
37Monitor
CVE-2026-10063629 days apartSiYuan before v3.8.4 Path Traversal via exportBrowserHTML folder
33Monitor
CVE-2026-6008464 days apartSiYuan before v3.7.4 Arbitrary File Deletion via removeTemplate
33Monitor
CVE-2026-6908683 days apartSiYuan before v3.7.3 Path Traversal via unvalidated avID
33Monitor
CVE-2026-54066123 days apartSiYuan: Path Traversal via Double URL Encoding in /assets/*path (publish mode arbitrary file─read)
31Monitor

Not on record for this CVE: patch commit or PR link · public bounty program.

Technical details

Attack conditions

Anyone who can reach it over the internet can trigger it.
Administrator privileges are required.
No user action is required.
No special conditions are required; it is repeatable.

If successful

Confidentiality
Integrity
Availability

Attack vector: Network
Attack complexity: Low
Privileges required: High
User interaction: None
Scope: X

Weakness class (CWE)

CWE-22 · Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

nvd-secondary

Root cause

A user-supplied file name is joined with the allowed directory, but the result is never checked to confirm it is still inside that directory.

The bug in code

The whole CWE-22 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

1const file = path.join(ROOT, req.query.name);
2res.sendFile(file);

Fixed

1const file = path.resolve(ROOT, req.query.name);
2if (!file.startsWith(ROOT + path.sep)) {
3  return res.sendStatus(400);
4}
5res.sendFile(file);

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Attack patterns (CAPEC)

ATT&CK techniques

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Change log

CVSS8.7 → 5.9Oct 28, 2026, 8:07 PM UTC
Severityhigh → mediumOct 28, 2026, 8:07 PM UTC
SSVC exploitation— → noneOct 26, 2026, 6:07 PM UTC
Exploit maturity— → noneOct 25, 2026, 3:07 PM UTC
Fix✗ → ✓Oct 25, 2026, 3:07 PM UTC

For records you follow, these changes also arrive as notifications. →

References

github.com/siyuan-note/siyuan/security/advisories/GHSA-6gmc-424x-xgpm

Show all references (1 more)

www.vulncheck.com/advisories/siyuan-3.5.4-before-3.8.7-sensitive-path-bypass-via-windows-extended-length-prefix

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

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