CVE-2026-116168: SiYuan before v3.8.7 Path Traversal Local File Read via MCP Asset Tool
Noroxi assessment
Priority: Monitor (action score 27/100)
- 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: 0.18% (FIRST EPSS).
- Someone with local access to the system can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
- 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 before 3.8.7 contains a path traversal vulnerability in the MCP asset tool because validateAssetUploadPaths relies on an incomplete sensitive-path blacklist that omits .env and other secret files. Authenticated attackers driving the MCP asset upload action can copy such local files into the workspace and read them back via /assets/ over HTTP.
- Published
- Oct 25, 2026
- Updated
- Nov 4, 2026
- EPSS
- 0.1% · 8th percentile
- CWE
- CWE-22
Report tools
Action score
27
Low priority for now.
- CVSS
- 27 / 40 · 6.9 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.1%
CISA SSVC decision
- Exploitation
- proof of concept
- Automatable
- no
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- —
- CNA · VulnCheck
- 6.9
- NVD has not scored this yet; the score shown is the CNA’s.
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/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 itNoroxi 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.
We use this product, ask for helpAffected 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.
—
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
- before 3.8.7affected · semver
Same product
siyuan-note: all recordsOther highest-scoring records for the same primary product.
- CVE-2026-66012SiYuan before v3.7.2 Unauthenticated Administrator Takeover via MCP40Plan
- CVE-2026-72811SiYuan before v3.7.4 SQL Injection via backlink search39Monitor
- CVE-2026-69085SiYuan before v3.7.3 SQL Injection via searchDocs39Monitor
Published before and after this one in the same product
- ← EarlierCVE-2026-116166Oct 25, 2026 · SiYuan 3.6.0 before 3.8.7 Cleartext Transmission via Unenforced networkServeTLS Setting30Monitor
- ← EarlierCVE-2026-116167Oct 25, 2026 · SiYuan 2.9.0 before 3.8.7 XSS via check-auth to Parameter30Monitor
- Later →CVE-2026-116169Oct 25, 2026 · SiYuan 2.10.0 before 3.8.7 Stored XSS via KaTeX \href in Math Blocks20Monitor
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.
- Published
- Fix recordedsame day
- TodayNov 13, 2026+19 d
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
- overtimepogreporter
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 packageName37Monitor
- CVE-2026-7479869 days apartSiYuan kernel Path Traversal via database_clean MCP tool37Monitor
- CVE-2026-10063629 days apartSiYuan before v3.8.4 Path Traversal via exportBrowserHTML folder33Monitor
- CVE-2026-6008464 days apartSiYuan before v3.7.4 Arbitrary File Deletion via removeTemplate33Monitor
- CVE-2026-6908683 days apartSiYuan before v3.7.3 Path Traversal via unvalidated avID33Monitor
- 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
- Someone with local access to the system can trigger it.
- No account or password is required.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- Integrity
- Availability
- Attack vector
- Local
- Attack complexity
- Low
- Privileges required
- None
- 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:L/AC:L/AT:N/PR:N/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 classA representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.
Vulnerable
const file = path.join(ROOT, req.query.name);
res.sendFile(file);Fixed
const file = path.resolve(ROOT, req.query.name);
if (!file.startsWith(ROOT + path.sep)) {
return res.sendStatus(400);
}
res.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)
- Path TraversalCAPEC-126likelihood: High · Very High
- Using Slashes and URL Encoding Combined to Bypass Validation LogicCAPEC-64likelihood: High · High
- Manipulating Web Input to File System CallsCAPEC-76likelihood: High · Very High
- Using Escaped Slashes in Alternate EncodingCAPEC-78likelihood: High · High
- Using Slashes in Alternate EncodingCAPEC-79likelihood: High · High
ATT&CK techniques
—
Change log
- SSVC exploitation— → poc
- Exploit maturity— → none
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
Show all references (1 more)Show less
Vendor advisories and official records. Exploit/PoC links are deliberately left out.