CVE-2026-73208
published 2026-08-28CVE-2026-73208: 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…
PriorityP346high7.4CVSS 3.1
AVNACHPRNUINSUCHIHAN
EPSS
0.31%
22.8th percentile
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.
Affected
5 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| dovecot | dovecot | — | — |
| open-xchange_gmbh | ox_dovecot_ce | >= 2.3.13 < 2.4.5 | 2.4.5 |
| open-xchange_gmbh | ox_dovecot_pro | >= 2.3.13 < 2.3.22.2 | 2.3.22.2 |
| open-xchange_gmbh | ox_dovecot_pro | >= 3.0.0 < 3.0.7 | 3.0.7 |
| open-xchange_gmbh | ox_dovecot_pro | >= 3.1.0 < 3.1.6 | 3.1.6 |
CVSS provenance
nvdv3.17.4HIGHCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
vendor_redhat7.4HIGH
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Red Hat
dovecot: Dovecot: Authentication bypass via incorrect OAuth2 token validation
vendor_redhat·2026-08-28·CVSS 7.4
CVE-2026-73208 [HIGH] CWE-303 dovecot: Dovecot: Authentication bypass via incorrect OAuth2 token validation
dovecot: Dovecot: Authentication bypass via incorrect OAuth2 token validation
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 con
GHSA
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 chec
ghsa_unreviewed·2026-08-28
CVE-2026-73208 [HIGH] CWE-287 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 chec
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 vers
No detection rules found.
No public exploits indexed.
Bugzilla
CVE-2026-73208 dovecot: Dovecot: Authentication bypass via incorrect OAuth2 token validation [fedora-all]
bugzilla·2026-09-01·CVSS 7.4
CVE-2026-73208 [HIGH] CVE-2026-73208 dovecot: Dovecot: Authentication bypass via incorrect OAuth2 token validation [fedora-all]
CVE-2026-73208 dovecot: Dovecot: Authentication bypass via incorrect OAuth2 token validation [fedora-all]
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.
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 config
Bugzilla
CVE-2026-73208 dovecot: Dovecot: Authentication bypass via incorrect OAuth2 token validation
bugzilla·2026-08-28·CVSS 7.4
CVE-2026-73208 [HIGH] CVE-2026-73208 dovecot: Dovecot: Authentication bypass via incorrect OAuth2 token validation
CVE-2026-73208 dovecot: Dovecot: Authentication bypass via incorrect OAuth2 token validation
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 Doveco
2026-08-28
Published