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TI-2026-73349 Aliases CVE-2026-104817

Missing rate limits in Misskey's unauthenticated RSS fetch API

Priority MEDIUM 44CWE-405Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-770.

Summary

Misskey from 12.112.1 until 2026.7.0 has an unauthenticated fetch-rss API that lacks rate limiting and response-size restrictions (CWE-770). The API also performs synchronous XML parsing. An unauthenticated remote attacker can trigger unbounded outbound HTTP requests, exhausting instance resources, amplifying requests toward third-party servers, or probing network-reachable services even when federation is disabled.

Written with Claude Haiku 5.5 from the sources below · 2026-10-28

Description from the CNA

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.0046 40th percentileScored 2026-11-07
Fix Fixed misskey (misskey-dev): 2026.7.0

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
misskey-devmisskey12.0.0 – 13.14.2; 2023.9.0-beta.1 to before 2026.7.02026.7.0Patch availableCNA
  • misskey Vendormisskey-dev Affected 12.0.0 – 13.14.2; 2023.9.0-beta.1 to before 2026.7.0 Fixed in 2026.7.0 Patch available CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:a:misskey:misskey:*:*:*:*:*:*:*:*——misskey-dev
  • cpe:2.3:a:misskey:misskey:*:*:*:*:*:*:*:* Versions — — ·misskey-dev

Remediation

Upgrade Misskey to version 2026.7.0, which fixes this issue. The sources list no advisory identifier for this fix.

Written with Claude Haiku 5.5 from the sources below · 2026-10-28

  • Fix · CNA misskey (misskey-dev) Fixed in 2026.7.0

Timeline

  1. 2026-10-13 Threatist record created from CVE-2026-104817

References

Other 3

  • TI-2025-18599 Misskey CSRF vulnerability due to insecure configuration of authentication cookie attributes CVSS 3.1HIGH 8.2
  • TI-2025-29081 Misskey CSS Style Injection Vulnerability In `MkUrlPreview` CVSS 3.1HIGH 7.2
  • TI-2025-40906 Misskey has a login rate limit bypass via spoofed X-Forwarded-For header CVSS 4.0MEDIUM 6.9
  • TI-2025-29276 Misskey Directory Traversal Vulnerability in AiScript via `Mk:api` CVSS 3.1HIGH 7.5
  • TI-2025-40839 misskey.js's export data contains private post data CVSS 4.0HIGH 7.1
  • TI-2025-29271 @misskey-dev/summaly Redirect Filter Bypass CVSS 4.0LOW 2.1
See all 38 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences