CVE-2026-4635

published 2026-05-22

CVE-2026-4635: Mattermost versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14 fail to archive the channel before removing persistent…

Priority P4 28 medium 5.3 CVSS 3.1

AV N AC H PR L UI N S U C N I N A H

Mattermost versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14 fail to archive the channel before removing persistent notifications which allows authenticated user to crash the server via timing the creation of persistent notification message between the server deleting existing persistent notifications and archiving the channel.. Mattermost Advisory ID: MMSA-2026-00637

Affected

12 ranges

Vendor	Product	Version range	Fixed in
github.com	mattermost_mattermost-server	>= 10.11.0 < 10.11.15	10.11.15
github.com	mattermost_mattermost-server	>= 11.4.0 < 11.4.5	11.4.5
github.com	mattermost_mattermost-server	>= 11.5.0 < 11.5.4	11.5.4
github.com	mattermost_mattermost-server	>= 11.6.0 < 11.6.1	11.6.1
mattermost	mattermost	10.11.0 – 10.11.14	—
mattermost	mattermost	11.4.0 – 11.4.4	—
mattermost	mattermost	11.5.0 – 11.5.3	—
mattermost	mattermost	11.6.0 – 11.6.0	—
mattermost	mattermost_server	>= 10.11.0 < 10.11.15	10.11.15
mattermost	mattermost_server	>= 11.4.0 < 11.4.5	11.4.5
mattermost	mattermost_server	>= 11.5.0 < 11.5.4	11.5.4
mattermost	mattermost_server	>= 11.6.0 < 11.6.1	11.6.1

CVSS provenance

nvd v3.1 5.3 MEDIUM CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H

cvelistv5 v3.1 6.5 MEDIUM CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

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CWE-362