CVE-2026-104817 Misskey: Lack of rate limiting and size restrictions in RSS fetching API
Unauthenticated attackers can exhaust resources and probe internal networks via the RSS fetching API due to missing rate limits and size restrictions.
- 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-2026-104817?
CVE-2026-104817 is a high-severity server-side request forgery vulnerability in misskey-dev misskey, published on 13 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Misskey is an open source, federated social media platform. From 12.112.1 until 2026.7.0, the unauthenticated fetch-rss API lacks rate limiting and response-size restrictions and performs synchronous XML parsing. An attacker can trigger unbounded outbound HTTP requests and synchronous parsing, exhausting instance resources, amplifying requests toward third-party servers, or probing network-reachable services even when federation is disabled. This issue is fixed in version 2026.7.0.
Which versions are affected by CVE-2026-104817?
How do I fix CVE-2026-104817?
No fix has been published for CVE-2026-104817 yet. Limit exposure of the affected software until one is available.
Upgrade, and send outbound requests through an allow-list that blocks internal addresses. More about Server-side request forgery.
Is CVE-2026-104817 being exploited?
There is no known exploitation of CVE-2026-104817 in the wild and no public exploit code.
Sources
Also known as GHSA-4x7v-qx8f-g3p8.