CVE-2026-6850
6.5
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Summary
Mattermost versions 11.7.x <= 11.7.2, 11.6.x <= 11.6.4, 10.11.x <= 10.11.19 fail to validate the length and content of message attachment field values, which allows an authenticated attacker to cause a denial of service for all users in a channel via a post containing a specially crafted payload that triggers catastrophic backtracking in the client-side markdown parser.. Mattermost Advisory ID: MMSA-2026-00658
Affected Software
| Vendor | Product | Version Range | Status |
|---|---|---|---|
| Mattermost | Mattermost | 11.7.0 <= 11.7.2 | affected |
| Mattermost | Mattermost | 11.6.0 <= 11.6.4 | affected |
| Mattermost | Mattermost | 10.11.0 <= 10.11.19 | affected |
| Mattermost | Mattermost | 11.8.0 | unaffected |
| Mattermost | Mattermost | 11.7.3 | unaffected |
| Mattermost | Mattermost | 11.6.5 | unaffected |
| Mattermost | Mattermost | 10.11.20 | unaffected |
Weaknesses
- CWE-1333: CWE-1333: Inefficient Regular Expression Complexity
ADP Enrichment
CISA ADP Vulnrichment
- SSVC:
- Exploitation: none
- Automatable: no
- Technical Impact: partial
References
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