---
title: "Security digest: July 23, 2026"
url: https://erroneo.us/security/2026-07-23/
description: "July 23, 2026 vulnerability digest: 3 critical advisories (Maven, npm). What to patch and who can relax."
type: security-digest-day
section: "Security Digest"
date_published: 2026-07-23
date_modified: 2026-07-23
publisher: erroneo.us
author: erroneo.us Security Desk
license: All rights reserved. Quote with attribution and a link.
---

# Security digest: July 23, 2026

3 critical advisories.

## Take stock

- npm: 2 critical advisories ( next-auth , @auth/core ). Check with npm audit (or: npm ls <package>) .
- Maven: 1 critical advisory ( com.alibaba:fastjson ). Check with mvn dependency:tree -Dincludes=<groupId>:<artifactId> .
- None of it touches your stack? Then there is nothing to do today. That is a result, not a failure to read carefully.

## Known exploited (CISA KEV)

None.

## Critical advisories

- [CVE-2026-16723](https://erroneo.us/security/cve/CVE-2026-16723/index.md) fastjson has a remote code execution (RCE) vulnerability — Maven com.alibaba:fastjson >= 1.2.68, <= 1.2.83 → no fix
- [CVE-2026-73421](https://erroneo.us/security/cve/CVE-2026-73421/index.md) Auth.js: Configuration errors can cause existence-based auth checks to fail open (auth object populated with an error) — npm next-auth >= 5.0.0-beta.0, <= 5.0.0-beta.31 → 5.0.0-beta.32
- [CVE-2026-73420](https://erroneo.us/security/cve/CVE-2026-73420/index.md) Auth.js: Email normalizer validates the address before Unicode normalization, allowing a homoglyph @ bypass — npm @auth/core >= 0.1.0, < 0.41.3 → 0.41.3; npm next-auth >= 4.10.3, < 4.24.15 → 4.24.15; npm next-auth >= 5.0.0-beta.1, <= 5.0.0-beta.31 → 5.0.0-beta.32

---
Source page: https://erroneo.us/security/2026-07-23/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt