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Fencer Vulns
high 7.4

CVE-2026-73208 json

An attacker that holds a token intended for a different purpose can authenticate, because when an OAuth2 token response does not contain a…

published 2026-08-28 2 mo ago modified 2026-09-03 2 mo ago also EUVD-2026-67680

cvss
7.4
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 24%
public exploits
0
none known

Summary

An attacker that holds a token intended for a different purpose can authenticate, because when an OAuth2 token response does not contain a scope claim, the audience claim is used in its place and checked against the configured required scopes. These are different concepts, and the audience claim does not describe what a token is allowed to do. A token that grants no relevant permissions can be accepted because its intended recipient value happens to match a configured scope name, granting access that should have been denied. It also hides an identity provider misconfiguration where scopes are not being issued at all. Ensure the identity provider issues a scope claim for all tokens used with Dovecot, and that configured scope names do not match audience values. 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-2026-73208

  • dovecot RHEL 9 1:2.3.16-18.el9_8.8
  • dovecot-mysql RHEL 9 1:2.3.16-18.el9_8.8
  • dovecot-pgsql RHEL 9 1:2.3.16-18.el9_8.8
  • dovecot-pigeonhole RHEL 9 1:2.3.16-18.el9_8.8
  • dovecot RHEL 10.2 1:2.3.21-19.el10_2.8
  • dovecot-mysql RHEL 10.2 1:2.3.21-19.el10_2.8
  • dovecot-pgsql RHEL 10.2 1:2.3.21-19.el10_2.8
  • dovecot-pigeonhole RHEL 10.2 1:2.3.21-19.el10_2.8

red hat advisories RHSA-2026:80825RHSA-2026:79371RHSA-2026:76763

  • 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 AlmaLinux 9 1:2.3.16-18.el9_8.8
  • dovecot-mysql AlmaLinux 9 1:2.3.16-18.el9_8.8
  • dovecot-pgsql AlmaLinux 9 1:2.3.16-18.el9_8.8
  • dovecot-pigeonhole AlmaLinux 9 1:2.3.16-18.el9_8.8
  • dovecot AlmaLinux 10 1:2.3.21-19.el10_2.8
  • dovecot-mysql AlmaLinux 10 1:2.3.21-19.el10_2.8
  • dovecot-pgsql AlmaLinux 10 1:2.3.21-19.el10_2.8
  • dovecot-pigeonhole AlmaLinux 10 1:2.3.21-19.el10_2.8

almalinux advisories ALSA-2026:80825ALSA-2026:79371ALSA-2026:76763

  • dovecot Rocky Linux 9 1:2.3.16-18.el9_8.8
  • dovecot Rocky Linux 10 1:2.3.21-19.el10_2.8
  • dovecot Rocky Linux 8 1:2.3.16-16.el8_10

rocky linux advisories RLSA-2026:80825RLSA-2026:79371RLSA-2026:76763

  • dovecot Alpine 3.24, Alpine 3.23 2.4.5-r0

alpine advisories ALPINE-CVE-2026-73208

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-2026-73208 updated cvss 7.4

dovecot: Dovecot: Authentication bypass via incorrect OAuth2 token validation

  • Red Hat Enterprise Linux AppStream (v. 8) dovecot 2.3.16-16.el8_10, dovecot-mysql 2.3.16-16.el8_10, dovecot-pgsql 2.3.16-16.el8_10, dovecot-pigeonhole 2.3.16-16.el8_10
    fixed: vendor fix RHSA-2026:76763
  • Red Hat Enterprise Linux AppStream (v. 9) dovecot 2.3.16-18.el9_8.8, dovecot-mysql 2.3.16-18.el9_8.8, dovecot-pgsql 2.3.16-18.el9_8.8, dovecot-pigeonhole 2.3.16-18.el9_8.8
    fixed: vendor fix RHSA-2026:80825
  • Red Hat Enterprise Linux AppStream (v. 10) dovecot 2.3.21-19.el10_2.8, dovecot-mysql 2.3.21-19.el10_2.8, dovecot-pgsql 2.3.21-19.el10_2.8, dovecot-pigeonhole 2.3.21-19.el10_2.8
    fixed: vendor fix RHSA-2026:79371
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) dovecot 2.3.16-18.el9_8.8
    fixed: vendor fix RHSA-2026:80825
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) dovecot-devel 2.3.21-19.el10_2.8, dovecot-debuginfo 2.3.21-19.el10_2.8, dovecot-debugsource 2.3.21-19.el10_2.8, dovecot-mysql-debuginfo 2.3.21-19.el10_2.8, dovecot-pgsql-debuginfo 2.3.21-19.el10_2.8, dovecot-pigeonhole-debuginfo 2.3.21-19.el10_2.8
    fixed: vendor fix RHSA-2026:79371
  • Red Hat Enterprise Linux CRB (v. 8) dovecot 2.3.16-16.el8_10
    fixed: vendor fix RHSA-2026:76763
  • 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
total
Assessed
2 mo ago

Exploit prediction

0.31% chance of exploitation in the next 30 days, higher than 24% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.4 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

Affected products

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

Classification

Weakness

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.