CVE-2026-40205

dovecot: An attacker that holds an OAuth2 token granting only part of the required scopes can authenticate, because when more...

CVE-2026-40205 is fixed in 12 products on 1 platform, first by SUSE-SU-2026:23595-1, released September 1, 2026. It is not reported as exploited. Patch Radar priority: Routine.

Routine
CVSS
5.9
medium
Exploitation
None reported
No vendor assessment
CISA KEV
Not listed
Not in the Known Exploited Vulnerabilities catalog
EPSS
0.0021
11th percentile

An attacker that holds an OAuth2 token granting only part of the required scopes can authenticate, because when more than one scope is required in the configuration, the remote token validation paths accept a token that carries only one of them, while the local token validation path correctly requires all of them. The configured authorization policy is not enforced, so a token that was granted only part of the required permissions is accepted where it should have been rejected. Use local token validation where tokens can be validated locally. Update to non-vulnerable version. No publicly available exploits are known.

Where it's fixed

ProductFixed inFixReleased
Linux
dovecot · Debian 12.15 (bookworm) 1:2.3.19.1+dfsg1-2.1+deb12u7 DEBIAN-CVE-2026-40205 Sep 10, 2026
dovecot · Debian 13.5 (trixie) 1:2.4.1+dfsg1-6+deb13u7 DEBIAN-CVE-2026-40205 Sep 10, 2026
dovecot · Debian 14 1:2.4.5+dfsg1-1 DEBIAN-CVE-2026-40205 Sep 10, 2026
dovecot · Fedora 43 1:2.4.5-1.fc43 FEDORA-2026-E8A6485109 Sep 10, 2026
dovecot-debuginfo · Fedora 43 1:2.4.5-1.fc43 FEDORA-2026-E8A6485109 Sep 10, 2026
dovecot-debugsource · Fedora 43 1:2.4.5-1.fc43 FEDORA-2026-E8A6485109 Sep 10, 2026
dovecot-devel · Fedora 43 1:2.4.5-1.fc43 FEDORA-2026-E8A6485109 Sep 10, 2026
dovecot-mysql · Fedora 43 1:2.4.5-1.fc43 FEDORA-2026-E8A6485109 Sep 10, 2026
dovecot-mysql-debuginfo · Fedora 43 1:2.4.5-1.fc43 FEDORA-2026-E8A6485109 Sep 10, 2026
dovecot-pgsql · Fedora 43 1:2.4.5-1.fc43 FEDORA-2026-E8A6485109 Sep 10, 2026
dovecot-pgsql-debuginfo · Fedora 43 1:2.4.5-1.fc43 FEDORA-2026-E8A6485109 Sep 10, 2026
dovecot-pigeonhole · Fedora 43 1:2.4.5-1.fc43 FEDORA-2026-E8A6485109 Sep 10, 2026
dovecot-pigeonhole-debuginfo · Fedora 43 1:2.4.5-1.fc43 FEDORA-2026-E8A6485109 Sep 10, 2026
dovecot23 · sles 15.6 2.3.21.1-150200.76.1 SUSE-SU-2026:4139-1 Sep 14, 2026
dovecot23 · sles 15.7 2.3.21.1-150200.76.1 SUSE-SU-2026:4139-1 Sep 14, 2026
dovecot24 · opensuse-leap 16.0 2.4.4-160000.2.1 OPENSUSE-SU-2026:21720-1 Sep 1, 2026
dovecot24 · sles 16.0 2.4.4-160000.2.1 SUSE-SU-2026:23595-1 Sep 1, 2026

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