CVE-2025-4981: 
Mattermost vulnerability analysis and mitigation

A critical vulnerability (CVE-2025-4981) was discovered in Mattermost affecting versions 10.5.x <= 10.5.5, 9.11.x <= 9.11.15, 10.8.x <= 10.8.0, 10.7.x <= 10.7.2, and 10.6.x <= 10.6.5. The vulnerability was disclosed on June 20, 2025, and involves a failure to sanitize filenames in the archive extractor, which could lead to remote code execution (NVD).

The vulnerability stems from improper filename sanitization in the archive extractor, allowing authenticated users to write files to arbitrary locations on the filesystem through path traversal sequences in filenames. This issue specifically impacts instances where file uploads and document search by content are enabled (FileSettings.EnableFileAttachments = true and FileSettings.ExtractContent = true), which are default settings. The vulnerability has been assigned a CVSS v3.1 base score of 9.9 (Critical) with the vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H, indicating high severity across confidentiality, integrity, and availability impacts (NVD).

The vulnerability poses a significant security risk as it potentially enables remote code execution on affected systems. When successfully exploited, attackers can write files to arbitrary locations on the filesystem, potentially compromising the entire system's security. The high CVSS score of 9.9 reflects the severe potential impact on system confidentiality, integrity, and availability (NVD).

Organizations using affected versions of Mattermost should immediately update to the latest patched versions. The vulnerability affects instances where file uploads and document search by content are enabled, which are default settings. If immediate updating is not possible, organizations should consider disabling these features by setting FileSettings.EnableFileAttachments and FileSettings.ExtractContent to false (NVD).