CVE-2023-26455: RMI was not requiring authentication when calling ChronosRMIService:setEventOrganizer. Attackers with local or adjacent network access could abuse the...

Description

RMI was not requiring authentication when calling ChronosRMIService:setEventOrganizer. Attackers with local or adjacent network access could abuse the RMI service to modify calendar items using RMI. RMI access is restricted to localhost by default. The interface has been updated to require authenticated requests. No publicly available exploits are known.

Metrics

CVSS 3.1

7.8/10

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

EPSS Probability

0.19%

8.4th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Open-Xchange	Open-Xchange Appsuite	< 7.10.6
Open-Xchange	Open-Xchange Appsuite	7.10.6

References

Timeline

Published: Nov 2, 2023
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2023-26455?

RMI was not requiring authentication when calling ChronosRMIService:setEventOrganizer. Attackers with local or adjacent network access could abuse the RMI service to modify calendar items using RMI. RMI access is restricted to localhost by default. The interface has been updated to require authenticated requests. No publicly available exploits are known.

How severe is CVE-2023-26455?

CVE-2023-26455 has a CVSS score of 7.8/10 (HIGH severity). The EPSS model estimates a 0.19% probability of exploitation in the next 30 days.

How do I fix CVE-2023-26455?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.