CVE-2026-85581 SiYuan before v3.8.2 Denial of Service via unauthenticated UI-process registration
Unauthenticated attackers can exhaust process memory by sending repeated requests to the UI-process registration endpoint, causing service degradation.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-85581?
CVE-2026-85581 is a high-severity denial of service vulnerability in siyuan-note siyuan, published on 4 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
SiYuan before v3.8.2 contains a denial of service vulnerability in the unauthenticated /api/system/uiproc endpoint that accepts and retains attacker-controlled process identifiers without size limits or authentication. Attackers can send repeated requests with unique identifiers to exhaust process memory and degrade service availability.
Weakness: CWE-770
Which versions are affected by CVE-2026-85581?
How do I fix CVE-2026-85581?
No fix has been published for CVE-2026-85581 yet. Limit exposure of the affected software until one is available.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-85581 being exploited?
There is no known exploitation of CVE-2026-85581 in the wild and no public exploit code.
Sources
Also known as GHSA-4qv4-f447-c9m2, GHSA-wv96-wmf5-xvj2.