CVE-2026-74800 SiYuan before v3.7.4 Stored XSS via assets endpoint
Authenticated attackers can upload malicious HTML assets to execute scripts with kernel API access when the workspace owner views them.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-74800?
CVE-2026-74800 is a critical cross-site scripting vulnerability in siyuan-note siyuan, published on 17 Aug 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Official description
SiYuan before v3.7.4 fails to set Content-Disposition and X-Content-Type-Options headers when serving arbitrary file assets, allowing stored cross-site scripting attacks. Authenticated attackers can upload HTML files as assets and execute scripts with full kernel API access when the workspace owner opens the asset link.
Weakness: CWE-79
Which versions are affected by CVE-2026-74800?
How do I fix CVE-2026-74800?
No fix has been published for CVE-2026-74800 yet. Limit exposure of the affected software until one is available.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-74800 being exploited?
There is no known exploitation of CVE-2026-74800 in the wild and no public exploit code.
Sources
Also known as GHSA-v4hj-628x-hq5x.