EUVD-2026-67664
GHSA-r364-r477-7mhc
Severity by source
AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Network delivery with no server-side auth needed; UI:R because THREAD command must be issued by client; purely availability impact.
Primary rating from Vendor (OX).
CVSS VectorVendor: OX
Lifecycle Timeline
2DescriptionCVE.org
An attacker that can send mail to a user can craft a message header that makes the IMAP THREAD command consume CPU disproportionate to the size of the message. When a mail client issues a THREAD command on the affected mailbox, this can cause degradation or denial of service for IMAP. Monitor system for abnormal CPU usage, kill the offending process and remove the offending message from the affected mailbox. Update to non-vulnerable version. No publicly available exploits are known.
AnalysisAI
CPU exhaustion in OX Dovecot's IMAP THREAD command allows a remote unauthenticated attacker to degrade or deny IMAP service by sending a specially crafted message header to any mailbox user. The vulnerability triggers when a mail client subsequently issues a THREAD command on the affected mailbox, causing disproportionate CPU consumption relative to message size. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | The attacker must be able to deliver email to the target user's mailbox - no authentication to the Dovecot server itself is required (PR:N per CVSS). … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS 3.1 score of 6.5 (AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H) accurately reflects the attack profile: network-accessible, low complexity, no authentication, but requiring user interaction in the form of a mail client issuing a THREAD command. … 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 vendor recommends updating to a non-vulnerable version; consult the Open-Xchange security advisory at https://documentation.open-xchange.com/dovecot/security/advisories/csaf/2026/oxdc-adv-2026-0003.json for the specific patched release, as no exact fix version was enumerated in the available intelligence. … Detailed patch versions, workarounds, and compensating controls in full report. |
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Same weakness CWE-400 – Uncontrolled Resource Consumption
View allSame technique Denial Of Service
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External POC / Exploit Code
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