title: Collapsed Reply Threads APIs leak message contents from private channels
description: Mattermost fails to check channel membership when accessing message threads, allowing an attacker to access arbitrary posts by using the message threads API.
problem types: CWE-862 Missing Authorization
affected:
{
defaultStatus: unaffected
product: Mattermost
vendor: Mattermost
versions:
lessThanOrEqual: 7.9.3, status: affected, version: 0, versionType: semver
lessThanOrEqual: 7.8.4, status: affected, version: 0, versionType: semver
lessThanOrEqual: 7.1.9, status: affected, version: 0, versionType: semver
status: affected, version: 7.10.0
status: unaffected, version: 7.9.3
status: unaffected, version: 7.8.4
status: unaffected, version: 7.1.9
status: unaffected, version: 7.10.1
}
metrics:
cvssV3_1: [
attackComplexity: LOW
attackVector: NETWORK
availabilityImpact: NONE
baseScore: 6.5
baseSeverity: MEDIUM
confidentialityImpact: HIGH
integrityImpact: NONE
privilegesRequired: LOW
scope: UNCHANGED
userInteraction: NONE
vectorString: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
version: 3.1
]
format: CVSS
scenarios: GENERAL
solutions: Update Mattermost to version v7.1.10, v7.8.5, v7.9.4, v7.10.1, or higher.