title: Stack exhaustion in PreparePostForClientWithEmbedsAndImages
description: Mattermost fails to validate links on external websites when constructing a preview for a linked website, allowing an attacker to cause a denial-of-service by a linking to a specially crafted webpage in a message.
problem types: CWE-400 Uncontrolled Resource Consumption
affected:
{
defaultStatus: unaffected
product: Mattermost
vendor: Mattermost
versions:
lessThanOrEqual: 7.8.2, status: affected, version: 0, versionType: semver
lessThanOrEqual: 7.9.1, status: affected, version: 0, versionType: semver
status: unaffected, version: 7.10.1
status: unaffected, version: 7.8.3
status: unaffected, version: 7.9.2
status: affected, version: 7.10.0
}
metrics:
cvssV3_1: [
attackComplexity: LOW
attackVector: NETWORK
availabilityImpact: HIGH
baseScore: 6.5
baseSeverity: MEDIUM
confidentialityImpact: NONE
integrityImpact: NONE
privilegesRequired: LOW
scope: UNCHANGED
userInteraction: NONE
vectorString: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
version: 3.1
]
format: CVSS
scenarios: GENERAL
solutions: Update Mattermost to version  v7.8.3, v7.9.2, 7.10.1 or higher.