Medium severity · published Jul 17, 2026
CVE-2026-8075
Posting a malicious markdown image crashes the Mattermost Desktop App
6.5
CVSS
0.4%
EPSS
No
On KEV
Description
Mattermost Desktop App versions <=6.2 5.5.13 6.0.2.0 fail to properly null check when checking for headers in the Mattermost Desktop App which allows any user to crash another channel members Desktop App via posting a malicious link with an embedded image that misses one of those headers. Mattermost Advisory ID: MMSA-2026-00668
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 36% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
MA
Mattermost · Mattermost
through 5.5.13; through 6.0.2 · source: vendor
MD
Mattermost Desktop · Mattermost
before 5.13.6; after 6.0.0 through 6.0.2; 6.2.0 before 6.2.1 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-8075
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-8075
Vendor Advisory
https://mattermost.com/security-updates
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