Skip to content
Fencer Vulns
low 3.1

CVE-2020-7957 json

The IMAP and LMTP components in Dovecot 2.3.9 before 2.3.9.3 mishandle snippet generation when many characters must be read to compute the…

published 2020-02-12 6 y ago modified 2026-06-17 4 mo ago also EUVD-2020-28877

cvss
3.1
version 3.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.9%
EPSS 1.9% chance of exploitation in 30 days, percentile 79%
public exploits
0
none known

Summary

The IMAP and LMTP components in Dovecot 2.3.9 before 2.3.9.3 mishandle snippet generation when many characters must be read to compute the snippet and a trailing > character exists. This causes a denial of service in which the recipient cannot read all of their messages.

Patch / fix

  • dovecot dovecot 2.3.9.3
  • dovecot24 openSUSE Tumbleweed 2.4.0-1.1
  • dovecot23 openSUSE Tumbleweed 2.3.16-1.6

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

  • dovecot Alpine 3.10, Alpine 3.9, Alpine 3.8 2.3.10.1-r0
  • dovecot Alpine 3.24, Alpine 3.23, Alpine 3.22 +11 more 2.3.9.3-r0

alpine advisories ALPINE-CVE-2020-7957

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 2.3.9.3-1

arch linux advisories AVG-1097

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-2020-7957 updated cvss 5.3

dovecot: specially crafted email can cause mailbox to have permanently unaccessible mail

  • 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

1.88% chance of exploitation in the next 30 days, higher than 79% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • openwall.com http://www.openwall.com/lists/oss-security/2020/02/12/2 referenced PoC, tagged "exploit" by a source, unverified
  • dovecot.org https://dovecot.org/pipermail/dovecot-news/2020-February/000430.html referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.0 3.1 CVSS:3.0/AC:H/AV:N/A:L/C:N/I:N/PR:N/S:U/UI:R
NVD 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
CNA 3.0 3.1 CVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:L
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:N/I:N/A:P

Classification

Weakness
  • CWE-20 Improper Input Validation

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.