siyuan: Origin Validation Error
CVE-2026-100642 is a high-severity origin validation error vulnerability in siyuan from Siyuan-note, with a CVSS 3.1 base score of 7.6 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, but only if a user takes part, for example by opening a link or file. The record lists version 3.8.4 as the first without the flaw, so updating siyuan to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.13% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update siyuan to 3.8.4 or a later version.
- Read the advisory on github.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
- Because the attack needs a user to take part, warn users about unexpected links and files related to this product until it is patched.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Siyuan-note | siyuan | 2.1.0 up to, but not including, 3.8.4 | 3.8.4 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- RequiredA user must take an action such as opening a file or link.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- LowSome restricted data can be read.
- Integrity
- LowLimited modification of data is possible.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:H. Scored by CNA (vulncheck.com).
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 7.2 | High | CNA (vulncheck.com) |
| CVSS 3.1 | 7.6 | High | CNA (vulncheck.com) |
Official description
SiYuan versions from v2.1.0 before v3.8.4 contain a cross-site request forgery vulnerability in the CheckAuth lock-screen pass-through branch that grants administrator access to loopback requests without validating Origin headers. Attackers can craft malicious web pages that force victims to terminate the kernel process, read workspace configuration and proxy settings, and trigger administrative actions via zero-credential cross-origin requests from the victim's browser.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Origin Validation Error
The product does not properly verify that the source of data or communication is valid.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: poc, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Other references
Other vulnerabilities in siyuan
- 7.5 High severity
- 7.4 High severity
- 7.7 High severity
- 7.5 High severity
- 7.1 High severity
- 8.1 High severity
Recent Origin Validation Error vulnerabilities
- 7.1 High severity
- 8.8 High severity
- 7.3 High severity
- 9.1 Critical severity
- 9.1 Critical severity
- 7.4 High severity
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