CVE-2026-42462

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.

CVSS v3.1 Score

7.0

HIGH

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:L

EPSS — Exploit Prediction

0.0017

Probability of exploitation

0.07%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-180 CWE-180

CWE-347 CWE-347

CWE-436 CWE-436

CWE-1289 CWE-1289

References

Other References

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

Frequently Asked Questions

What is 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. It has a CVSS v3.1 base score of 7.0 (HIGH).

How severe is CVE-2026-42462? +

CVE-2026-42462 has a CVSS v3.1 score of 7.0 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0017, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-42462? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

Related Vulnerabilities

CVE-2026-45022

go-git is an extensible git implementation library written in pure Go. Prior to 5.19.0 and 6.0.0-alpha.3, go-git may parse malformed …

CVE-2025-29787

`zip` is a zip library for rust which supports reading and writing of simple ZIP files. In the archive extraction …

CVE-2026-48721 8.6

Warp is an agentic development environment. From 0.2025.10.08.08.12.stable_00 until 0.2026.05.06.15.42.stable_01, Warp contains a command execution permission-check bypass in the default …

CVE-2026-49984 7.7

Kestra is an open-source, event-driven orchestration platform. Prior to 1.0.45 and 1.3.23, the local internal-storage backend validates user-supplied paths for …

CVE-2025-43716 5.8

A directory traversal vulnerability exists in Ivanti LANDesk Management Gateway through 4.2-1.9. By appending %3F.php to the URI of the …

CVE-2025-33194 5.7

NVIDIA DGX Spark GB10 contains a vulnerability in SROOT firmware, where an attacker could cause improper processing of input data. …