CVE-2026-6339
Published: May 18, 2026
Modified: May 18, 2026
CVSS v3.1
4.3
Description
Mattermost versions 11.5.x <= 11.5.1, 11.4.x <= 11.4.3 fail to validate the X-Requested-With header on the burn-on-read reveal endpoint which allows an authenticated channel member to force the reveal of a burn-on-read message without recipient consent via a crafted Markdown image tag.. Mattermost Advisory ID: MMSA-2026-00636
| Vendor | Product | Versions |
|---|---|---|
Mattermost | Mattermost | affected 11.5.0 - <= 11.5.1affected 11.4.0 - <= 11.4.3unaffected 11.6.0unaffected 11.5.2unaffected 11.4.4 |
Weaknesses (CWE)
CVSS v3.1 Details
CVSS v3.1 Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality
Integrity
Availability
References
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