CVE-2026-100637 json
SiYuan before v3.8.4 Path Traversal via checkoutRepo sessionID
published last mo. modified last mo. also EUVD-2026-87731
- cvss
- 7.6
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.6%
- EPSS 0.6% chance of exploitation in 30 days, percentile 46%
- public exploits
- 0
- none known
Summary
SiYuan versions before v3.8.4 contain a path traversal vulnerability in the checkoutRepo endpoint that allows authenticated administrators to write JSON files outside the workspace. Attackers can supply a sessionID parameter containing directory traversal sequences to overwrite arbitrary JSON files in pre-existing kernel-writable directories outside workspace boundaries.
Patch / fix
- siyuan-note siyuan 3.8.4
Is CVE-2026-100637 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.
Check with FencerCISA SSVC
- Exploitation
- Proof of concept is public
- Automatable
- no
- Technical impact
- partial
- Assessed
- last mo.
Exploit prediction
0.55% chance of exploitation in the next 30 days, higher than 46% of all scored CVEs (FIRST EPSS, 2026-11-09).
Exploits and checks
- github.com https://github.com/siyuan-note/siyuan/security/advisories/GHSA-jhmh-hr4g-c5g2 referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 4.0 | 8.3 | CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:N/VI:H/VA:L/SC:N/SI:H/SA:L |
| CNA | 3.1 | 7.6 | CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:N/I:H/A:L |
| CNA | 4.0 | 8.3 | CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:N/VI:H/VA:L/SC:N/SI:H/SA:L/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 |
Affected products
- siyuan-note siyuan
Classification
- Weakness
-
- CWE-73 External Control of File Name or Path
References
-
github.com
/siyuan-note/siyuan/security/advisories/GHSA-jhmh-hr4g-c5g2
vendor-advisory, exploit
-
vulncheck.com
/advisories/siyuan-before-3.8.4-path-traversal-via-checkoutrepo-sessionid
third-party-advisory
Sources
- CVE List CVE-2026-100637
- NVD CVE-2026-100637
Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.
CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.