Memory Exhaustion via Malicious 7zip File Upload_CVE-2026-6340

4.3 / 10

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L

Description

Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13, 11.4.x <= 11.4.3 fail to validate 7zip archive structure before processing which allows an authenticated attacker to cause server memory exhaustion and denial of service via uploading a specially crafted 7zip file with excessive folder declarations.. Mattermost Advisory ID: MMSA-2026-00573

Basic Information

ID CVE-2026-6340

Source Mattermost

Published May 18, 2026 at 07:08

Affected Product

Vendor Mattermost

Product Mattermost

Version 11.5.0

Affected Versions Mattermost Mattermost 11.5.0
Mattermost Mattermost 10.11.0
Mattermost Mattermost 11.4.0

CWE Classification

CWE-789

References

mattermost.com /security-updates

{
    "lastseen": "",
    "description": "Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13, 11.4.x <= 11.4.3 fail to validate 7zip archive structure before processing which allows an authenticated attacker to cause server memory exhaustion and denial of service via uploading a specially crafted 7zip file with excessive folder declarations.. Mattermost Advisory ID: MMSA-2026-00573",
    "published": "2026-05-18T07:08:56.863Z",
    "modified": "2026-05-18T07:08:56.863Z",
    "type": "cve",
    "title": "Memory Exhaustion via Malicious 7zip File Upload",
    "source": "Mattermost",
    "references": "https://mattermost.com/security-updates",
    "id": "CVE-2026-6340",
    "bulletinFamily": "",
    "cwe": [
        "CWE-789"
    ],
    "cvelist": null,
    "sourceData": "Mattermost Mattermost 11.5.0\nMattermost Mattermost 10.11.0\nMattermost Mattermost 11.4.0",
    "sourceHref": "",
    "cvss": {
        "score": 4.3,
        "severity": "MEDIUM",
        "vector": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L",
        "version": "3.1"
    },
    "cvss2": [],
    "cvss3": {
        "version": "",
        "vectorString": "",
        "baseScore": 0,
        "baseSeverity": "",
        "attackVector": "",
        "attackComplexity": "",
        "privilegesRequired": "",
        "userInteraction": "",
        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
            "version": "",
            "vectorString": "",
            "baseScore": 0,
            "baseSeverity": "",
            "attackVector": "",
            "attackComplexity": "",
            "privilegesRequired": "",
            "userInteraction": "",
            "scope": "",
            "confidentialityImpact": "",
            "integrityImpact": "",
            "availabilityImpact": ""
        }
    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "Mattermost",
    "version": "11.5.0",
    "vendor": "Mattermost",
    "ai_description": "",
    "ai_severity": "",
    "ai_vendor": "",
    "ai_product": "",
    "ai_version": "",
    "ai_score": 0
}