CVE-2026-85175: SiYuan before v3.8.2 TLS Private Key Disclosure via getFile

Severity: high (CVSS 8.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-03 · updated 2026-09-08
Weakness: CWE-552

Description

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).

Affected products

Go Github.Com/Siyuan-Note/Siyuan/Kernel: before 0.0.0-20260819144130-256d73aa7f94 — fixed in 0.0.0-20260819144130-256d73aa7f94
siyuan-note siyuan: before 3.8.2 — fixed in 3.8.2

How to fix

Upgrade to a fixed version: Go Github.Com/Siyuan-Note/Siyuan/Kernel 0.0.0-20260819144130-256d73aa7f94; siyuan-note siyuan 3.8.2. Check the vendor advisory for mitigations.

References

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