How severe is CVE-2026-23933?

CVE-2026-23933 has a CVSS 3.x base score of 9.1, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability none.

Is CVE-2026-23933 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (28th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-23933?

CVE-2026-23933 affects Zabbix. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-23933?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2026-23933 published?

CVE-2026-23933 was published on 2026-08-18 and last updated on 2026-09-23.

CVE-2026-23933

CVE-2026-23933 is a critical-severity vulnerability in Zabbix with a CVSS 3.x base score of 9.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-259.

Key facts

Severity: Critical (CVSS 3.x base score 9.1)
CVSS v4: 7.7
EPSS exploit prediction: 0% (28th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-259
Affected product: Zabbix
Published: 2026-08-18
Last modified: 2026-09-23

Description

In Zabbix 7.4 the cryptographic key used for signing Frontend sessions has been erroneously written to the database seed. Currently the only known exploitation scenario is for deployments that utilize both - SAML authentication and guest users. In such cases the key can be used to forge valid session cookies, potentially leading to unauthorized access. For other Zabbix deployments this does not have a known impact.

Frequently asked questions

What is CVE-2026-23933?: In Zabbix 7.4 the cryptographic key used for signing Frontend sessions has been erroneously written to the database seed. Currently the only known exploitation scenario is for deployments that utilize both - SAML authentication and guest users. In such cases the key can be used to forge valid session cookies, potentially leading to unauthorized access. For other Zabbix deployments this does not have a known impact.
How severe is CVE-2026-23933?: CVE-2026-23933 has a CVSS 3.x base score of 9.1, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability none.
Is CVE-2026-23933 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (28th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-23933?: CVE-2026-23933 affects Zabbix. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-23933?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2026-23933 published?: CVE-2026-23933 was published on 2026-08-18 and last updated on 2026-09-23.

References

https://support.zabbix.com/browse/ZBX-28071

Affected products (1)

cpe:2.3:a:zabbix:zabbix:*:*:*:*:*:*:*:*

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