{
"id": "GHSA-37j2-3vv8-cf24",
"aliases": [
"CVE-2026-5755"
],
"details": "Mattermost versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.2, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14 fail to validate the TIFF IFD offset in the image header before allocating memory, which allows authenticated users with file upload or posting permissions to cause a denial of service (server OOM) via uploading a crafted TIFF file or posting a URL that serves one.. Mattermost Advisory ID: MMSA-2026-00648",
"summary": "Mattermost doesn't validate the TIFF IFD offset in the image header before allocating memory",
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "11.6.0"
},
{
"fixed": "11.6.1"
}
]
}
],
"package": {
"name": "github.com/mattermost/mattermost-server",
"ecosystem": "Go"
},
"versions": [
"11.6.0"
]
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "11.5.0"
},
{
"fixed": "11.5.4"
}
]
}
],
"package": {
"name": "github.com/mattermost/mattermost-server",
"ecosystem": "Go"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "11.4.0"
},
{
"fixed": "11.4.5"
}
]
}
],
"package": {
"name": "github.com/mattermost/mattermost-server",
"ecosystem": "Go"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "10.11.0"
},
{
"fixed": "10.11.15"
}
]
}
],
"package": {
"name": "github.com/mattermost/mattermost-server",
"ecosystem": "Go"
}
}
],
"modified": "2026-06-29T22:41:10Z",
"severity": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"
}
],
"published": "2026-05-26T13:30:15Z",
"references": [
{
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-5755",
"type": "ADVISORY"
},
{
"url": "https://github.com/mattermost/mattermost/commit/d37c2d9d50b50963dabd92153adf7ed52016769a",
"type": "WEB"
},
{
"url": "https://github.com/mattermost/mattermost",
"type": "PACKAGE"
},
{
"url": "https://mattermost.com/security-updates",
"type": "WEB"
}
],
"schema_version": "1.4.0",
"database_specific": {
"cwe_ids": [
"CWE-400"
],
"severity": "MODERATE",
"github_reviewed": true,
"nvd_published_at": "2026-05-22T11:16:23Z",
"github_reviewed_at": "2026-06-29T22:41:10Z"
}
}