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OX Dovecot CVE-2026-52687

| EUVDEUVD-2026-67679 MEDIUM
Uncontrolled Resource Consumption (CWE-400)
2026-08-28 OX GHSA-f7hp-q869-25g3
Denial Of Service Ox Dovecot Pro Ox Dovecot Ce Open Xchange Gmbh
6.5
CVSS 3.1 · Vendor: OX
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Severity by source

Vendor (OX) PRIMARY
6.5 MEDIUM
AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
vuln.today AI
6.5 MEDIUM

Network-accessible IMAP service requires only valid low-privilege credentials; impact is purely availability as the attack is resource exhaustion with no data access or integrity consequence.

3.1 AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
4.0 AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
SUSE
MEDIUM
qualitative
Red Hat
6.5 MEDIUM
qualitative

Primary rating from Vendor (OX).

CVSS VectorVendor: OX

Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

Lifecycle Timeline

2
Patch available
Aug 28, 2026 - 13:17 EUVD
Analysis Generated
Aug 28, 2026 - 12:20 vuln.today

DescriptionCVE.org

An attacker that has valid credentials can select a compression algorithm for the IMAP connection whose decompression state requires a large amount of memory, and open several such connections. The memory limit of the process is reached with only a few connections, terminating the process and all connections it handles, which can cause degradation or denial of service for IMAP. Disable IMAP compression. Alternatively limit the number of connections handled by a single imap-login process, though this has a performance impact. Update to non-vulnerable version. No publicly available exploits are known.

AnalysisAI

IMAP compression in OX Dovecot Pro and OX Dovecot CE allows any authenticated user to exhaust the memory of the imap-login process by negotiating a memory-intensive decompression algorithm across multiple simultaneous connections. The process crashes after only a few such connections, terminating all sessions it manages and causing denial of service for all active IMAP users sharing that process. …

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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata

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Execution
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Vulnerability AssessmentAI

Exploitation Exploitation requires a valid IMAP account on the target server - any low-privilege authenticated user qualifies per the CVSS PR:L metric. … Additional conditions and limiting factors are described in the full assessment.
Risk Assessment The CVSS 3.1 score of 6.5 with vector AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H accurately reflects a network-accessible, low-complexity attack requiring only authenticated (low-privilege) access, with high availability impact and no confidentiality or integrity consequence. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in.
Exploit Scenario Full exploit scenario with step-by-step reproduction available after sign-in.
Remediation The primary remediation is to update to the non-vulnerable version of OX Dovecot Pro or OX Dovecot CE as specified in the vendor advisory at https://documentation.open-xchange.com/dovecot/security/advisories/csaf/2026/oxdc-adv-2026-0003.json; exact fixed version numbers should be confirmed there. … Detailed patch versions, workarounds, and compensating controls in full report.
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Vendor StatusVendor

SUSE

Severity: Moderate
Product Status
SUSE Linux Enterprise Server 12 SP5-LTSS Fixed
SUSE Linux Enterprise Server LTSS Extended Security 12 SP5 Fixed
openSUSE Leap 16.0 Fixed
openSUSE Tumbleweed Fixed
SUSE Linux Enterprise Server 16.0 Affected

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CVE-2026-52687 vulnerability details – vuln.today
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