title: Lack of URL normalization allows rendering previews for disallowed domains
description: Mattermost fails to normalize UTF confusable characters when determining if a preview should be generated for a hyperlink, allowing an attacker to trigger link preview on a disallowed domain using a specially crafted link.
problem types: CWE-20 Improper Input Validation
affected:
{
defaultStatus: unaffected
product: Mattermost
vendor: Mattermost
versions:
lessThan: 7.1.9, status: affected, version: 0, versionType: semver
lessThan: 7.8.4, status: affected, version: 0, versionType: semver
lessThan: 7.9.3, status: affected, version: 0, versionType: semver
status: unaffected, version: 7.1.9
status: unaffected, version: 7.8.4
status: unaffected, version: 7.9.3
status: unaffected, version: 7.10
}
metrics:
cvssV3_1: [
attackComplexity: LOW
attackVector: NETWORK
availabilityImpact: NONE
baseScore: 4.3
baseSeverity: MEDIUM
confidentialityImpact: NONE
integrityImpact: LOW
privilegesRequired: LOW
scope: UNCHANGED
userInteraction: NONE
vectorString: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
version: 3.1
]
format: CVSS
scenarios: GENERAL
solutions: Update Mattermost to version v7.1.9, v7.8.4, v7.9.3, v7.10, or higher.