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

Quick assessment

Affected
fedify-dev fedify
Exploitation
Public or AI PoC available; prioritize validation
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Fedify是Hong Minhee个人开发者的一个 TypeScript 库。用于构建由 ActivityPub 和其他标准支持的联邦服务器应用程序。 Fedify 1.9.11之前版本、1.10.10之前版本、2.0.18之前版本、2.1.14之前版本和2.2.3之前版本存在安全漏洞，该漏洞源于攻击者利用JSON-LD功能重构文档而不改变链接数据签名，可能导致篡改第三方签名活动。

CVSS 7.0 · High EPSS 0.25% · P15

Possible ATT&CK Techniques 1 AI

T1601 · Modify System Image

Affected Version Matrix 5

VendorProduct Version RangeStatus
fedify-dev fedify >= 2.2.0, < 2.2.3 affected
>= 2.1.0, < 2.1.14 affected
>= 2.0.0, < 2.0.18 affected
>= 1.10.0, < 1.10.10 affected
< 1.9.11 affected
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I. Basic Information for CVE-2026-42462

Vulnerability Information
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Vulnerability Title
Fedify has an LD-Signature Bypass via JSON-LD Named-Graph Restructuring
Source: CVE Program / CVE List V5
Vulnerability 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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:L
Source: CVE Program / CVE List V5
Vulnerability Type
不正确的行为次序：规范化之前验证
Source: CVE Program / CVE List V5
Vulnerability Title
Fedify 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Fedify是Hong Minhee个人开发者的一个 TypeScript 库。用于构建由 ActivityPub 和其他标准支持的联邦服务器应用程序。 Fedify 1.9.11之前版本、1.10.10之前版本、2.0.18之前版本、2.1.14之前版本和2.2.3之前版本存在安全漏洞，该漏洞源于攻击者利用JSON-LD功能重构文档而不改变链接数据签名，可能导致篡改第三方签名活动。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
fedify-dev fedify >= 2.2.0, < 2.2.3 -

II. Public POCs for CVE-2026-42462

# POC Description Source Link Shenlong Link
AI-Generated POC Premium
Qwen3.6-35B-A3B · 8971 chars
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Vulnerability reproduction recording (real sandbox build + trigger, exclusive)
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Trigger conditions & impact
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POC zip download
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III. Intelligence Information for CVE-2026-42462

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Vendor Advisories for CVE-2026-42462 (1)

Vendor Pages for CVE-2026-42462 (1)

IV. Related Vulnerabilities

Same product: fedify
Same vendor: fedify-dev
Same weakness: CWE-180

V. Comments for CVE-2026-42462

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