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CVE-2026-50131
Published:June 10, 2026
Updated:June 28, 2026
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.
Affected Packages
@fedify/fedify (NPM):
Affected version(s) >=2.2.0 <2.2.4
Fix Suggestion:
Update to version 2.2.4
@fedify/vocab-runtime (NPM):
Affected version(s) >=2.2.0 <2.2.4
Fix Suggestion:
Update to version 2.2.4
@fedify/vocab-runtime (NPM):
Affected version(s) >=2.1.0 <2.1.15
Fix Suggestion:
Update to version 2.1.15
@fedify/fedify (NPM):
Affected version(s) >=2.1.0 <2.1.15
Fix Suggestion:
Update to version 2.1.15
@fedify/vocab-runtime (NPM):
Affected version(s) >=2.0.0 <2.0.19
Fix Suggestion:
Update to version 2.0.19
@fedify/fedify (NPM):
Affected version(s) >=0.11.2 <1.9.12
Fix Suggestion:
Update to version 1.9.12
@fedify/fedify (NPM):
Affected version(s) >=2.0.0 <2.0.19
Fix Suggestion:
Update to version 2.0.19
@fedify/fedify (NPM):
Affected version(s) >=1.10.0 <1.10.11
Fix Suggestion:
Update to version 1.10.11
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CVSS v4
Base Score:
8.8
Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
NONE
User Interaction
NONE
Vulnerable System Confidentiality
HIGH
Vulnerable System Integrity
LOW
Vulnerable System Availability
LOW
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
8.6
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
LOW
Availability
LOW
Weakness Type (CWE)
Incorrect Parsing of Numbers with Different Radices
Improper Validation of Syntactic Correctness of Input
Server-Side Request Forgery (SSRF)
EPSS
Base Score:
0.27