Medium severity · published Aug 1, 2024
CVE-2024-39839
Remote username set to an arbitrary string by remote user
4.3
CVSS
0.3%
EPSS
No
On KEV
Description
Mattermost versions 9.9.x <= 9.9.0, 9.5.x <= 9.5.6, 9.7.x <= 9.7.5, 9.8.x <= 9.8.1 fail to disallow users to set their own remote username, when shared channels were enabled, which allows a user on a remote to set their remote username prop to an arbitrary string, which would be then synced to the local server as long as the user hadn't been synced before.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
None
Integrity
Low
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 27% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
MA
Mattermost · Mattermost
9.9.0; 9.5.0 through 9.5.6; 9.7.0 through 9.7.5; 9.8.0 through 9.8.1 · source: vendor
MS
Mattermost Server · Mattermost
9.5.0 before 9.5.7; 9.7.0 before 9.7.6; 9.8.0 before 9.8.2; 9.9.0 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2024-39839
CVE.org
https://www.cve.org/CVERecord?id=CVE-2024-39839
Vendor Advisory
https://mattermost.com/security-updates
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