Review reviewHigh

CVE-2026-42462

fedify-dev fedify

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.

CVSS: 7
EPSS: 0.17%
CISA KEV: Not listed
Published: 2026.06.11

PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV

Exploit probability0.17%

Technical severityCVSS 7

Vulnerability overview

Affected product and versions

Product: fedify-dev fedify
Affected versions: >= >= 2.2.0, < 2.2.3, >= >= 2.1.0, < 2.1.14, >= >= 2.0.0, < 2.0.18, >= >= 1.10.0, < 1.10.10, >= < 1.9.11
Fixed versions: No verified fixed-version field is available yet

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide

1
Identify
Confirm that fedify-dev fedify and an affected version are present.
2
Prioritize
Combine exploitation signals with asset exposure and business criticality.
3
Remediate
Follow the vendor advisory or supported update path and preserve rollback options.
4
Verify
Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:L
CWE: CWE-1289, CWE-180, CWE-347, CWE-436