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Fencer Vulns
low 3.1

CVE-2026-52681 json

Sieve CPU resource usage is tracked in the compiled script, so an attacker that has valid credentials can reset the accounting by repeatedl…

published 2026-08-28 2 mo ago modified 2026-09-03 2 mo ago also EUVD-2026-67678

cvss
3.1
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 22%
public exploits
0
none known

Summary

Sieve CPU resource usage is tracked in the compiled script, so an attacker that has valid credentials can reset the accounting by repeatedly changing the active script. Compiled script files are also not removed when a script is deleted or renamed. The configured Sieve CPU limit can be bypassed, allowing sustained CPU consumption, and the leftover files increase disk consumption. Both can cause degradation of service for mail delivery. Monitor system for abnormal CPU usage and disk consumption. 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-2026-52681

  • 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

suse advisories SUSE-SU-2026:4139-1SUSE-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 Alpine 3.24, Alpine 3.23 2.4.5-r0

alpine advisories ALPINE-CVE-2026-52681

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

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-2026-52681 updated cvss 3.1

dovecot: Dovecot: Denial of Service via Sieve script manipulation

  • Red Hat Enterprise Linux 8 dovecot, dovecot-mysql, dovecot-pgsql, dovecot-pigeonhole Red Hat Enterprise Linux 9 dovecot, dovecot-mysql, dovecot-pgsql, dovecot-pigeonhole Red Hat Enterprise Linux 10 dovecot
    affected: workaround, no fix available “Fix deferred”
  • Red Hat Enterprise Linux 6 dovecot, dovecot-mysql, dovecot-pgsql, dovecot-pigeonhole Red Hat Enterprise Linux 7 dovecot, dovecot-mysql, dovecot-pgsql, dovecot-pigeonhole
    not affected: vulnerable code not present

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
2 mo ago

Exploit prediction

0.30% chance of exploitation in the next 30 days, higher than 22% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

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

Affected products

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

Classification

Weakness
  • CWE-1050 Excessive Platform Resource Consumption within a Loop

References

Sources

Fencer Vulns 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.