Crafted message attachment causes client-side denial of service via markdown parser regex backtracking in Mattermost
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
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| Mattermost | Mattermost | unaffected |
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Configuration 1 [-]
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No data.
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| Mattermost | Mattermost |
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Vendor Solution
Update Mattermost to versions 11.8.0, 11.7.3, 11.6.5, 10.11.20 or higher.
No CVSS v4.0
No CVSS v3.0
No CVSS v2
This CVE is not in the KEV list.
Exploit prediction score: < 1% (0.420% probability within 30 days)
| Link | Providers |
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| https://mattermost.com/security-updates |
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| Metrics |
ssvc
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| First Time appeared |
Mattermost
Mattermost mattermost |
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| Vendors & Products |
Mattermost
Mattermost mattermost |
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| Description | 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 | |
| Title | Crafted message attachment causes client-side denial of service via markdown parser regex backtracking in Mattermost | |
| Weaknesses | CWE-1333 | |
| References |
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| Metrics |
cvssV3_1
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