CVE-2026-42007
An attacker that has valid credentials can use a Sieve script with the editheader extension to trigger a use-after-free in the mail…
- Published
- Updated
- Reserved
- Assigned by
- OX
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.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| OXCNA (assigner) | 3.1 | Critical9.1 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:H |
| NVDNVD · Deferred | 3.1 | Critical9.1 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:H |
- EPSS (exploitation in 30 days)
- 0.34% · top 72% of all CVEs (5 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: Critical 9.1.
Weakness
Affected products
Open-Xchange GmbH · OX Dovecot Pro
- affected 2.3.0 – < 2.3.22.2
- affected 3.0.0 – < 3.0.7
- affected 3.1.0 – < 3.1.6
Open-Xchange GmbH · OX Dovecot CE
- affected 2.3.0 – < 2.4.5
References (1)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2026-42007)Record last updated .