CVE-2026-52687 Open-Xchange GmbH CVE debrief

Who should care

IMAP service administrators and users with valid credentials; consider mitigations to prevent potential denial of service. This vulnerability may impact organizations relying on IMAP services for email access and management. Security teams should review configurations and plan for potential updates or mitigations. Vulnerability management processes should include assessment of affected systems and prioritization of remediation efforts based on risk and exposure.

Technical summary

An attacker with valid credentials can select a compression algorithm for an IMAP connection that requires a large amount of memory, potentially causing a denial of service. The process memory limit can be reached with only a few connections, terminating the process and all connections it handles. This issue affects IMAP service configurations and users with valid credentials. Additional technical analysis may be needed to fully understand the vulnerability's impact.

Defensive priority

Medium priority due to potential for denial of service; consider mitigations

Recommended defensive actions

• Disable IMAP compression as a temporary mitigation
• Limit the number of connections handled by a single imap-login process
• Update to a non-vulnerable version when available
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

Evidence is limited; primary official records indicate a potential denial of service vulnerability. Further verification needed. Additional review of related systems and configurations may be required to assess full scope. Limited source details are available for validation.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.