Vulnerability in Siyuan-Note Siyuan
CVE-2026-85175
SiYuan versions <= 3.8.1 (fixed in v3.8.2) contain an incomplete blocklist in the IsForbiddenAbsPath() function (kernel/util/path_guard.go), which only blocks conf/conf.json by exact match and does not restrict the TLS private key (conf/key.pem) or CA private key (conf/ca.key) stored in the same conf/ directory. Because the getFile handler skips the blocklist for RoleAdministrator and all authenticated users receive RoleAdministrator in v3.8.1, any user (or any client on a default no-auth-code instance) can retrieve these private keys via POST /api/file/getFile. On deployments with TLS enabled, this allows decryption of captured HTTPS traffic (key.pem) and forging of certificates trusted by clients that imported SiYuan's CA (ca.key).
Published · last modified .
CVSS v3 metric
CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.003 (24.0th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 24th percentile — 24.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.003 · change: +0.001
Affected products
Weakness classification (CWE)
References
- github.com/siyuan-note/siyuan/security/advisories/GHSA-4wwp-f6gw-6qm5 (vendor-advisory)
- www.vulncheck.com/advisories/siyuan-before-3.8.2-tls-private-key-disclosure-via… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-85175?
- CVE-2026-85175 is a high-severity vulnerability in Siyuan-Note Siyuan, classified under Files or Directories Accessible to External Parties. CVSS score: 8.8/10. Published 2026-09-03.
- How severe is CVE-2026-85175?
- High severity. CVSS v3 base score is 8.8 out of 10.