# CVE-2026-42462

## Summary

- **CVE ID:** CVE-2026-42462
- **Severity:** HIGH
- **CVSS Score:** 7 (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:L)
- **CWE:** CWE-180, CWE-347, CWE-436, CWE-1289
- **Published:** Jun 10, 2026
- **Last Modified:** Jun 11, 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.

## Affected Products

- fedify-dev — fedify (>= 2.2.0, < 2.2.3)
- fedify-dev — fedify (>= 2.1.0, < 2.1.14)
- fedify-dev — fedify (>= 2.0.0, < 2.0.18)
- fedify-dev — fedify (>= 1.10.0, < 1.10.10)
- fedify-dev — fedify (< 1.9.11)

## References

- [CNA](https://github.com/fedify-dev/fedify/security/advisories/GHSA-9rfg-v8g9-9367)
- [CNA](https://github.com/fedify-dev/fedify/releases/tag/2.2.3)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.17%
- **EPSS Percentile:** 6.7

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-10._