CVE-2024-23184

NameCVE-2024-23184
DescriptionHaving a large number of address headers (From, To, Cc, Bcc, etc.) becomes excessively CPU intensive. With 100k header lines CPU usage is already 12 seconds, and in a production environment we observed 500k header lines taking 18 minutes to parse. Since this can be triggered by external actors sending emails to a victim, this is a security issue. An external attacker can send specially crafted messages that consume target system resources and cause outage. One can implement restrictions on address headers on MTA component preceding Dovecot. No publicly available exploits are known.
SourceCVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
ReferencesDLA-3860-1, DSA-5752-1
Debian Bugs1078876

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
dovecot (PTS)jessie, jessie (lts)1:2.2.13-12~deb8u9vulnerable
stretch (security)1:2.2.27-3+deb9u7fixed
stretch (lts), stretch1:2.2.27-3+deb9u8fixed
buster, buster (lts)1:2.3.4.1-5+deb10u8fixed
buster (security)1:2.3.4.1-5+deb10u7fixed
bullseye1:2.3.13+dfsg1-2+deb11u1vulnerable
bullseye (security)1:2.3.13+dfsg1-2+deb11u2fixed
bookworm (security), bookworm1:2.3.19.1+dfsg1-2.1+deb12u1fixed
sid, trixie1:2.3.21.1+dfsg1-1fixed

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
dovecotsourcejessie(unfixed)end-of-life
dovecotsourcestretch(not affected)
dovecotsourcebuster(not affected)
dovecotsourcebullseye1:2.3.13+dfsg1-2+deb11u2DLA-3860-1
dovecotsourcebookworm1:2.3.19.1+dfsg1-2.1+deb12u1DSA-5752-1
dovecotsource(unstable)1:2.3.21.1+dfsg1-11078876

Notes

[buster] - dovecot <not-affected> (Vulnerable code not present)
[stretch] - dovecot <not-affected> (Vulnerable code not present)
https://www.openwall.com/lists/oss-security/2024/08/15/3
Fixed by: https://github.com/dovecot/core/commit/8e4c42dbb3c770fcdbc396f2abcf1bc228ec548d (2.3.21.1)
Fixed by: https://github.com/dovecot/core/commit/cee08202c759a3bdf185d998dcf888ebd1bc6e36 (2.3.21.1)
Fixed by: https://github.com/dovecot/core/commit/0bae091859c905dc335f21eed01347e6b8338672 (2.3.21.1)
Fixed by: https://github.com/dovecot/core/commit/a1c9b0409454e45937bf7e9c3685f5e91d6a5a43 (2.3.21.1)
Fixed by: https://github.com/dovecot/core/commit/da61d20311da34f22944c6111a0b97ea2a1f8a47 (2.3.21.1)
Fixed by: https://github.com/dovecot/core/commit/1481c04f02df7647f520df65d63df7626bf0ee32 (2.3.21.1)
Introduced by: https://github.com/dovecot/core/commit/469fcd3bdd7df40bb8f4d131121f3bfbceade02a (2.3.10)

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