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Fencer Vulns
high 7.5

CVE-2019-10691 json

The JSON encoder in Dovecot before 2.3.5.2 allows attackers to repeatedly crash the authentication service by attempting to authenticate wi…

published 2019-04-24 7 y ago modified 2026-06-17 4 mo ago also EUVD-2019-2485

cvss
7.5
version 3.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
2.8%
EPSS 2.8% chance of exploitation in 30 days, percentile 86%
public exploits
0
none known

Summary

The JSON encoder in Dovecot before 2.3.5.2 allows attackers to repeatedly crash the authentication service by attempting to authenticate with an invalid UTF-8 sequence as the username.

Patch / fix

  • dovecot dovecot 2.3.5.2
  • dovecot Debian 14, Debian 13, Debian 12 1:2.3.4.1-4

debian advisories DEBIAN-CVE-2019-10691

  • dovecot23 SLE Module for Server Applications 15 2.3.3-4.13.1

suse advisories SUSE-SU-2019:0997-1

  • dovecot24 openSUSE Tumbleweed 2.4.0-1.1
  • dovecot23 openSUSE Tumbleweed 2.3.16-1.6
  • dovecot23 openSUSE Leap 15.0 2.3.3-lp150.11.1

opensuse advisories openSUSE-SU-2025:14715-1openSUSE-SU-2024:10726-1openSUSE-SU-2019:1312-1

  • dovecot Alpine 3.24, Alpine 3.23, Alpine 3.22 +14 more 2.3.6-r0

alpine advisories ALPINE-CVE-2019-10691

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

  • dovecot Arch Linux 2.3.5.2-1

arch linux advisories AVG-950

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-2019-10691 updated cvss 7.5

dovecot: Mishandling invalid UTF-8 characters by JSON encoder leading to possible DoS attack.

  • Red Hat Enterprise Linux 5 dovecot Red Hat Enterprise Linux 6 dovecot, dovecot-mysql, dovecot-pgsql, dovecot-pigeonhole Red Hat Enterprise Linux 7 dovecot, dovecot-mysql, dovecot-pgsql, dovecot-pigeonhole Red Hat Enterprise Linux 8 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

Exploit prediction

2.80% chance of exploitation in the next 30 days, higher than 86% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.0 7.5 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:N/I:N/A:P

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.