Vulnerability in Fedify-Dev Fedify

CVE-2026-42462

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.

Published · last modified .

CVSS v3 metric

CVSS v3 base score 7.0 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:L.

EPSS exploit prediction

EPSS: 0.002 (6.5th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 6th percentile — 6.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-42462: held from 0.002 to 0.002.

EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: -0.001

Affected products

  • Fedify-Dev Fedify — versions >= 2.2.0, < 2.2.3, >= 2.1.0, < 2.1.14, >= 2.0.0, < 2.0.18

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-42462?
CVE-2026-42462 is a high-severity vulnerability in Fedify-Dev Fedify, classified under CWE-180. CVSS score: 7.0/10. Published 2026-06-10.
How severe is CVE-2026-42462?
High severity. CVSS v3 base score is 7.0 out of 10.