Mattermost versions 11.3.x <= 11.3.0 fail to preserve the redacted state of burn-on-read posts during deletion which allows channel members to access unrevealed burn-on-read message contents via the WebSocket post deletion event.. Mattermost Advisory ID: MMSA-2026-00579
{
"cwe_ids": [
"CWE-201"
],
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/2xxx/CVE-2026-2578.json",
"cna_assigner": "Mattermost",
"unresolved_ranges": [
{
"extracted_events": [
{
"introduced": "11.3.0"
},
{
"last_affected": "11.3.0"
}
],
"source": "AFFECTED_FIELD"
}
]
}