An attacker that has valid credentials can use a Sieve script with the editheader extension to trigger a use-after-free in the mail editing code, and to write memory contents beyond the intended buffer into the delivered mail. This causes memory leak and opportunity to do memory corruption during mail delivery, which can crash the delivery process and may allow execution of arbitrary code in the context of that process. Disable the Sieve editheader extension. Update to non-vulnerable version. No publicly available exploits are known.
Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Tue, 01 Sep 2026 14:45:00 +0000

Type Values Removed Values Added
First Time appeared Open-xchange
Open-xchange ox Dovecot Ce
Open-xchange ox Dovecot Pro
Vendors & Products Open-xchange
Open-xchange ox Dovecot Ce
Open-xchange ox Dovecot Pro

Tue, 01 Sep 2026 12:15:00 +0000

Type Values Removed Values Added
Title Use-After-Free in OX Dovecot Sieve Editheader Extension Allows Potential Code Execution dovecot: Dovecot: Arbitrary Code Execution via Sieve editheader use-after-free
Weaknesses CWE-825
References
Metrics threat_severity

None

threat_severity

Important


Fri, 28 Aug 2026 21:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Fri, 28 Aug 2026 14:45:00 +0000

Type Values Removed Values Added
Title Use-After-Free in OX Dovecot Sieve Editheader Extension Allows Potential Code Execution

Fri, 28 Aug 2026 11:30:00 +0000

Type Values Removed Values Added
Description An attacker that has valid credentials can use a Sieve script with the editheader extension to trigger a use-after-free in the mail editing code, and to write memory contents beyond the intended buffer into the delivered mail. This causes memory leak and opportunity to do memory corruption during mail delivery, which can crash the delivery process and may allow execution of arbitrary code in the context of that process. Disable the Sieve editheader extension. Update to non-vulnerable version. No publicly available exploits are known.
Weaknesses CWE-416
References
Metrics cvssV3_1

{'score': 9.1, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:H'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: OX

Published:

Updated: 2026-08-28T15:54:24.354Z

Reserved: 2026-04-23T11:15:21.199Z

Link: CVE-2026-42007

cve-icon Vulnrichment

Updated: 2026-08-28T14:32:38.212Z

cve-icon NVD

Status : Received

Published: 2026-08-28T12:16:29.260

Modified: 2026-08-28T20:17:30.057

Link: CVE-2026-42007

cve-icon Redhat

Severity : Important

Publid Date: 2026-08-28T10:12:25Z

Links: CVE-2026-42007 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-09-01T14:45:04Z

Weaknesses