Umbraco CMS before 17.7.2 and 18.2.2 contains an authentication bypass vulnerability that allows unauthenticated attackers to register attacker-controlled OAuth redirect URIs by poisoning the Host header. Attackers send signed-in users authorization links using response_mode=form_post to capture codes, then redeem them via HTTP Basic client credentials to hijack back-office sessions and execute code through Razor templates.
Advisories
No advisories yet.
Fixes
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
References
History
Tue, 27 Oct 2026 13:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | Umbraco CMS before 17.7.2 and 18.2.2 contains an authentication bypass vulnerability that allows unauthenticated attackers to register attacker-controlled OAuth redirect URIs by poisoning the Host header. Attackers send signed-in users authorization links using response_mode=form_post to capture codes, then redeem them via HTTP Basic client credentials to hijack back-office sessions and execute code through Razor templates. | |
| Title | Umbraco CMS before 17.7.2 and 18.2.2 Account Takeover via Host Header Poisoning | |
| First Time appeared |
Umbraco
Umbraco umbraco Cms |
|
| Weaknesses | CWE-601 | |
| CPEs | cpe:2.3:a:umbraco:umbraco_cms:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Umbraco
Umbraco umbraco Cms |
|
| References |
|
|
| Metrics |
cvssV3_1
|
Projects
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Status: PUBLISHED
Assigner: VulnCheck
Published:
Updated: 2026-10-27T13:07:49.671Z
Reserved: 2026-10-27T11:25:13.186Z
Link: CVE-2026-117553
No data.
Status : Awaiting Analysis
Published: 2026-10-27T14:16:35.840
Modified: 2026-10-27T16:03:45.247
Link: CVE-2026-117553
No data.
OpenCVE Enrichment
Updated: 2026-10-27T16:15:04Z
Weaknesses