CVE-2026-6339
4.3
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
Summary
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
Affected Software
| Vendor | Product | Version Range | Status |
|---|---|---|---|
| Mattermost | Mattermost | 11.5.0 <= 11.5.1 | affected |
| Mattermost | Mattermost | 11.4.0 <= 11.4.3 | affected |
| Mattermost | Mattermost | 11.6.0 | unaffected |
| Mattermost | Mattermost | 11.5.2 | unaffected |
| Mattermost | Mattermost | 11.4.4 | unaffected |
Weaknesses
- CWE-346: CWE-346: Origin Validation Error
ADP Enrichment
CISA ADP Vulnrichment
- SSVC:
- Exploitation: none
- Automatable: no
- Technical Impact: partial
References
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