CVE-2026-50131
HighCVSS 8.6Exploitation Probability (EPSS)
Low risk19th percentile - higher than 19% of all known CVEs
Summary
Fedify is a TypeScript library for building federated server apps powered by ActivityPub. In versions 0.11.2 and prior, the IPv4 validation logic is incomplete, potentially allowing SSRF bypass.
Risk Assessment
Incomplete IPv4 address validation may allow attackers to access internal network resources, posing a significant security risk to the application.
Recommendation
It is recommended to upgrade to versions 1.9.12, 1.10.11, 2.0.19, 2.1.15, or 2.2.4, which contain security patches.
Original NVD description (English source)
Fedify is a TypeScript library for building federated server apps powered by ActivityPub. Fedify previously addressed SSRF/internal network access in GHSA-p9cg-vqcc-grcx by adding public URL validation before runtime document and media fetching. However, the IPv4 validation logic present starting in version 0.11.2 and prior to versions 1.9.12, 1.10.11, 2.0.19, 2.1.15, and 2.2.4 appears incomplete. The `validatePublicUrl()` protection relies on `isValidPublicIPv4Address()` to reject non-public IPv4 destinations. The function blocks common private and local ranges such as `10.0.0.0/8`, `127.0.0.0/8`, `169.254.0.0/16`, `172.16.0.0/12`, and `192.168.0.0/16`, but it still treats several special-use, reserved, multicast, benchmarking, and carrier-grade NAT IPv4 ranges as valid public destinations. Because this validation is used as an SSRF defense before outbound fetches, this appears to be an incomplete mitigation or bypass class for the previous SSRF issue. Versions 1.9.12, 1.10.11, 2.0.19, 2.1.15, and 2.2.4 contain an updated patch.