What’s Vulnerable › Vulnerabilities

CVE-2026-104817: Misskey: Lack of rate limiting and size restrictions in RSS fetching API

• Severity: high (CVSS 8.7 v4.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-13 · updated 2026-10-16
• Weakness: CWE-405

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.

Affected products

• misskey-dev misskey: from 12.0.0, <= 13.14.2; from 2023.9.0-beta.1, < 2026.7.0

References

• https://github.com/misskey-dev/misskey/commit/a12ee2e5d72c40252e11a164b2231667c9697667
• https://github.com/misskey-dev/misskey/releases/tag/2026.7.0
• https://github.com/misskey-dev/misskey/security/advisories/GHSA-4x7v-qx8f-g3p8

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