CVE-2023-26455
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedRMI 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.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceChronosRMIService RMI interface lacked authentication enforcement on the setEventOrganizer method, allowing adjacent or local attackers to modify calendar entries without credentials. RMI access is default-restricted to localhost, limiting the attack surface. The vendor has addressed this by updating the interface to require authenticated requests.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data< 7.10.6= 7.10.6CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Local
- Complexity
- Low
- Privileges
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify installed Open Xchange Appsuite versionQuery the package manager or use the command 'oxversion' (if available) to retrieve the installed version of Open Xchange Appsuite. Alternatively, check the /opt/open-xchange/etc/Version.properties or similar version file if accessible.Affected if The installed version is less than 7.10.6 or exactly equals 7.10.6
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Verify RMI bind address configurationInspect the RMI configuration files in the Open Xchange deployment, typically found in /opt/open-xchange/etc/ or similar. Look for settings controlling the RMI bind address, such as 'rmi.host' or 'java.rmi.server.hostname'.Affected if RMI is bound to 0.0.0.0 or any IP other than 127.0.0.1/localhost, exposing the service to adjacent networks
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Confirm ChronosRMIService is runningCheck for running Java processes related to Chronos or the RMI registry. Use 'jps -l' or check for processes containing 'chronos' in the name. Verify the RMI registry is active on the default RMI port (1099) or configured port.Affected if ChronosRMIService is active and the RMI registry is accessible on a non-localhost interface
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Test RMI interface accessibilityFrom a non-localhost host on the same network, attempt to connect to the RMI registry (e.g., using 'rmi://target:1099/' or a Java RMI client tool). Verify if the ChronosRMIService can be looked up without authentication.Affected if The RMI interface is reachable from a remote host and the setEventOrganizer method can be invoked without credentials
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Check for authentication enforcement on ChronosRMIServiceIf you have access to logs or can perform a test invocation, verify whether the setEventOrganizer method enforces authentication. Review server logs for authentication-related messages when the method is called.Affected if The setEventOrganizer method executes without requiring authentication credentials
You are affected if your Open Xchange Appsuite version is less than or equal to 7.10.6 AND the RMI service is accessible from non-localhost addresses, allowing unauthenticated modification of calendar entries.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scoped7.10.6
Apply vendor patches to address the missing authentication in ChronosRMIService. Ensure RMI remains localhost-bound unless explicitly required, and verify after patching that the interface properly enforces authentication.
Open Xchange Appsuite 7.10.6 or later (latest stable release)
- 1. Identify the current installed version of Open Xchange Appsuite using the admin interface or system inventory
- 2. Confirm the version is either below 7.10.6 or exactly 7.10.6
- 3. Plan the upgrade during a maintenance window following standard backup procedures
- 4. Upgrade to Open Xchange Appsuite version 7.10.6 or later (preferably the latest stable release)
- 5. After upgrade, verify the RMI service now requires authentication for ChronosRMIService:setEventOrganizer calls
- 6. If RMI was exposed beyond localhost, ensure network access controls still restrict RMI to localhost as per default configuration
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation1.0 h
- Testing2.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2023-26455 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2023-26455 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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