CVE-2026-117553

Exploitation

Not assessed. CISA has not published an exploitation assessment for this record, and it is not in the KEV catalog. That is an absence of assessment, not a finding of no risk.

SSVC decision

Not assessed by CISA

EPSS probability

0.49% probability of exploitation activity in the next 30 days.

EPSS percentile

Equal to or higher than the score of 42.3% of scored records. A rank, not a probability.

NVD base score

7.7 (CVSS v4.0), scored by the NVD independently of the CNA.

NVD CVSS vector

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

NVD analysis status

Awaiting Analysis. NVD last modified this record on 2026-10-27.

Red Hat severity

No Red Hat rating. Red Hat rates the CVEs that affect its products.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

Published

2026-10-27 13:07Z1 DAY AGO

Last updated

2026-10-27 13:07Z1 DAY AGO

Reserved

2026-10-27

Assigning CNA

VulnCheck

Record state

PUBLISHED

Severity

High (CVSS 7.7)

CNA CVSS vector

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Weaknesses

• CWE-601URL Redirection to Untrusted Site ('Open Redirect')Base

Data version

5.2

Document digest

531ba6cbca3674c44f03d3a7680d5b1500007bff27ef356239c7580a267d9409

• github.comPatch Commithttps://github.com/umbraco/Umbraco-CMS/commit/490b9b27dcbb8fb3fe868a36203590968b0569d6patch
• github.comhttps://github.com/umbraco/Umbraco-CMSproduct
• github.comGitHub Security Advisory (GHSA-rpv9-qp4c-g469)https://github.com/umbraco/Umbraco-CMS/security/advisories/GHSA-rpv9-qp4c-g469vendor-advisory
• github.comhttps://github.com/umbraco/Umbraco-CMS/blob/release-18.2.1/src/Umbraco.Cms.Api.Management/Middleware/BackOfficeAuthorizationInitializationMiddleware.cs#L74-L112technical-description
• www.vulncheck.comVulnCheck Advisory: Umbraco CMS before 17.7.2 and 18.2.2 Account Takeover via Host Header Poisoninghttps://www.vulncheck.com/advisories/umbraco-cms-before-17.7.2-and-18.2.2-account-takeover-via-host-header-poisoningthird-party-advisory