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Fencer Intel
critical 9.1

CVE-2026-42007 json

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…

published 2mo ago modified 2mo ago also EUVD-2026-67672

cvss
9.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 28%
public exploits
0
none known

Summary

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.

Patch / fix

  • Open-Xchange GmbH OX Dovecot Pro 2.3.22.2, 3.0.7, 3.1.6
  • Open-Xchange GmbH OX Dovecot CE 2.4.5
  • dovecot Debian 12 1:2.3.19.1+dfsg1-2.1+deb12u7
  • dovecot Debian 13 1:2.4.1+dfsg1-6+deb13u7
  • dovecot Debian 14 1:2.4.5+dfsg1-1

debian advisories DEBIAN-CVE-2026-42007

  • dovecot RHEL 9 1:2.3.16-18.el9_8.8
  • dovecot-mysql RHEL 9 1:2.3.16-18.el9_8.8
  • dovecot-pgsql RHEL 9 1:2.3.16-18.el9_8.8
  • dovecot-pigeonhole RHEL 9 1:2.3.16-18.el9_8.8
  • dovecot RHEL 10.2 1:2.3.21-19.el10_2.8
  • dovecot-mysql RHEL 10.2 1:2.3.21-19.el10_2.8
  • dovecot-pgsql RHEL 10.2 1:2.3.21-19.el10_2.8
  • dovecot-pigeonhole RHEL 10.2 1:2.3.21-19.el10_2.8

red hat advisories RHSA-2026:80825RHSA-2026:79371RHSA-2026:76763

  • dovecot23 SLES for SAP 15 SP6, SLES for SAP 15 SP5, SLES for SAP 15 SP4 +8 more 2.3.21.1-150200.76.1
  • dovecot24 SLES for SAP applications 16.0, SLES 16.0 2.4.4-160000.2.1
  • dovecot22 SLES LTSS Extended Security 12 SP5, SLES 12 SP5-LTSS 2.2.31-19.40.1

suse advisories SUSE-SU-2026:4139-1SUSE-SU-2026:3919-1SUSE-SU-2026:23595-1

  • dovecot24 openSUSE Leap 16.0 2.4.4-160000.2.1
  • dovecot24 openSUSE Tumbleweed 2.4.5-1.1

opensuse advisories openSUSE-SU-2026:21720-1openSUSE-SU-2026:11629-1

  • dovecot AlmaLinux 9 1:2.3.16-18.el9_8.8
  • dovecot-mysql AlmaLinux 9 1:2.3.16-18.el9_8.8
  • dovecot-pgsql AlmaLinux 9 1:2.3.16-18.el9_8.8
  • dovecot-pigeonhole AlmaLinux 9 1:2.3.16-18.el9_8.8
  • dovecot AlmaLinux 10 1:2.3.21-19.el10_2.8
  • dovecot-mysql AlmaLinux 10 1:2.3.21-19.el10_2.8
  • dovecot-pgsql AlmaLinux 10 1:2.3.21-19.el10_2.8
  • dovecot-pigeonhole AlmaLinux 10 1:2.3.21-19.el10_2.8

almalinux advisories ALSA-2026:80825ALSA-2026:79371ALSA-2026:76763

  • dovecot Rocky Linux 9 1:2.3.16-18.el9_8.8
  • dovecot Rocky Linux 10 1:2.3.21-19.el10_2.8
  • dovecot Rocky Linux 8 1:2.3.16-16.el8_10

rocky linux advisories RLSA-2026:80825RLSA-2026:79371RLSA-2026:76763

  • dovecot Alpine 3.24, Alpine 3.23 2.4.5-r0

alpine advisories ALPINE-CVE-2026-42007

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Is CVE-2026-42007 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

Check with Fencer

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-42007 updated cvss 9.1

dovecot: Dovecot: Arbitrary Code Execution via Sieve editheader use-after-free

  • Red Hat Enterprise Linux 6 dovecot, dovecot-mysql, dovecot-pgsql, dovecot-pigeonhole
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 7 dovecot, dovecot-mysql, dovecot-pgsql, dovecot-pigeonhole
    affected: workaround, no fix available
  • Red Hat Enterprise Linux AppStream (v. 8) dovecot 2.3.16-16.el8_10, dovecot-mysql 2.3.16-16.el8_10, dovecot-pgsql 2.3.16-16.el8_10, dovecot-pigeonhole 2.3.16-16.el8_10
    fixed: vendor fix RHSA-2026:76763
  • Red Hat Enterprise Linux AppStream (v. 9) dovecot 2.3.16-18.el9_8.8, dovecot-mysql 2.3.16-18.el9_8.8, dovecot-pgsql 2.3.16-18.el9_8.8, dovecot-pigeonhole 2.3.16-18.el9_8.8
    fixed: vendor fix RHSA-2026:80825
  • Red Hat Enterprise Linux AppStream (v. 10) dovecot 2.3.21-19.el10_2.8, dovecot-mysql 2.3.21-19.el10_2.8, dovecot-pgsql 2.3.21-19.el10_2.8, dovecot-pigeonhole 2.3.21-19.el10_2.8
    fixed: vendor fix RHSA-2026:79371
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) dovecot 2.3.16-18.el9_8.8
    fixed: vendor fix RHSA-2026:80825
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) dovecot-devel 2.3.21-19.el10_2.8, dovecot-debuginfo 2.3.21-19.el10_2.8, dovecot-debugsource 2.3.21-19.el10_2.8, dovecot-mysql-debuginfo 2.3.21-19.el10_2.8, dovecot-pgsql-debuginfo 2.3.21-19.el10_2.8, dovecot-pigeonhole-debuginfo 2.3.21-19.el10_2.8
    fixed: vendor fix RHSA-2026:79371
  • Red Hat Enterprise Linux CRB (v. 8) dovecot 2.3.16-16.el8_10
    fixed: vendor fix RHSA-2026:76763

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
2mo ago

Exploit prediction

0.35% chance of exploitation in the next 30 days, higher than 28% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 3.1 9.1 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:H

Affected products

  • Open-Xchange GmbH OX Dovecot Pro
  • Open-Xchange GmbH OX Dovecot CE

Classification

Weakness

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.