CVE-2026-42462

Fedify has an LD-Signature Bypass via JSON-LD Named-Graph Restructuring

State: Published
Severity: 7.0 High
Published: Jun 10, 2026
Updated: Jun 11, 2026
Reserved: Apr 27, 2026

Description

Fedify is a TypeScript library for building federated server apps powered by ActivityPub. Prior to versions 1.9.11, 1.10.10, 2.0.18, 2.1.14, and 2.2.3, an attacker can make use of JSON-LD features to restructure a JSON-LD document that would change how Fedify interprets it without changing its Linked Data Signature, allowing them to alter a third-party signed activity they have received. Versions 1.9.11, 1.10.10, 2.0.18, 2.1.14, and 2.2.3 fix the issue.

Scores

CVSS	Score	Vector	Source
3.1	7.0 High	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:L	GitHub_M

Weaknesses

CWE-180 Incorrect Behavior Order: Validate Before Canonicalize
CWE-347 Improper Verification of Cryptographic Signature
CWE-436 Interpretation Conflict
CWE-1289 Improper Validation of Unsafe Equivalence in Input

Affected Products

Product	Versions
fedifyfedify-dev	>= 2.2.0, < 2.2.3Affected >= 2.1.0, < 2.1.14Affected >= 2.0.0, < 2.0.18Affected >= 1.10.0, < 1.10.10Affected < 1.9.11Affected

References

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