CVE-2026-15541 will-moss Isaiah Master Websocket server.go Server.Handle authorization
Remote attackers can bypass authorization in the Isaiah Master Websocket server by manipulating the Agent argument in the Server.Handle function.
- 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-2026-15541?
CVE-2026-15541 is a medium-severity missing authorization vulnerability in will-moss Isaiah, published on 13 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
A flaw has been found in will-moss Isaiah up to 1.36.9. The impacted element is the function Server.Handle of the file app/server/server/server.go of the component Master Websocket Handler. Executing a manipulation of the argument Agent can lead to missing authorization. It is possible to launch the attack remotely. The pull request to fix this issue awaits acceptance.
Which versions are affected by CVE-2026-15541?
How do I fix CVE-2026-15541?
No fix has been published for CVE-2026-15541 yet. Limit exposure of the affected software until one is available.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-15541 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-15541 exists.
Sources
Also known as GHSA-ch9v-gm7f-9q33.