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.
References3
Metrics
- CVSS 4.0
-
8.7
HIGH
Score source: CNA
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:L/SI:N/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - EPSS — exploit probability
- 0% percentile: 40 · as of 11 November 2026
- CWE
- CWE-405CWE-770CWE-918
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.