High
Path traversal in integration action URL leading to arbitrary API execution via system admin’s auth token.
Type: advisorySources: OSV
Mattermost versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14 fail to check integration URL for path traversal which allows an malicious authenticated user to call an arbitrary API via system admin Mattermost auth token using via path traversal in integration action URL.. Mattermost Advisory ID: MMSA-2026-00640
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2026-4858
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 5 Nov 2026, 00:54 UTC · Revision 1
Source evidence
Path traversal in integration action URL leading to arbitrary API execution via system admin’s auth token.
core-osv · Original sourcePublished 21 May 2026, 08:12 UTC
Mattermost versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14 fail to check integration URL for path traversal which allows an malicious authenticated user to call an arbitrary API via system admin Mattermost auth token using via path traversal in integration action URL.. Mattermost Advisory ID: MMSA-2026-00640
osv:CVE-2026-4858
Complete source record
{
"id": "478f1804cbbf1d753aa7972f339e03b181b72c9b39dacb9087975e6d16263d6a",
"url": "https://osv.dev/vulnerability/CVE-2026-4858",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "Path traversal in integration action URL leading to arbitrary API execution via system admin’s auth token.",
"summary": "Mattermost versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14 fail to check integration URL for path traversal which allows an malicious authenticated user to call an arbitrary API via system admin Mattermost auth token using via path traversal in integration action URL.. Mattermost Advisory ID: MMSA-2026-00640",
"evidence": "osv:CVE-2026-4858",
"products": [],
"severity": "high",
"structured": {
"id": "CVE-2026-4858",
"aliases": [
"CVE-2026-4858",
"GHSA-c4r7-j7pp-r8mp",
"GO-2026-5311"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:H"
}
],
"affected": [
{
"ranges": [
{
"repo": "https://github.com/mattermost/mattermost",
"type": "GIT",
"events": [
{
"introduced": "5b955468ea1ea8b56c0fb10feb258a36a767d7bb"
},
{
"fixed": "f6760151c4a7b4b9d0807fa18892aaf24a3e190e"
},
{
"introduced": "2a1ac98bd3fae587927adf9340ba266c8c02018e"
},
{
"fixed": "292d4b7ea15b49a29989129758f25be37aec946e"
},
{
"introduced": "9f2616376582893035a7e3cb38b0fab648bba4e8"
},
{
"fixed": "fff6ab3a5851dc47c65bd636281f5c678fe9de25"
},
{
"introduced": "d4f4e78835e86e2e76f76bfe797623076f5c9835"
},
{
"last_affected": "d4f4e78835e86e2e76f76bfe797623076f5c9835"
}
],
"database_specific": {
"extracted_events": [
{
"cpe": "cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*",
"range": [
{
"introduced": "10.11.0"
},
{
"fixed": "10.11.15"
}
],
"source": "CPE_RANGE"
},
{
"cpe": "cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*",
"range": [
{
"introduced": "11.4.0"
},
{
"fixed": "11.4.5"
}
],
"source": "CPE_RANGE"
},
{
"cpe": "cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*",
"range": [
{
"introduced": "11.5.0"
},
{
"fixed": "11.5.4"
}
],
"source": "CPE_RANGE"
},
{
"cpe": "cpe:2.3:a:mattermost:mattermost_server:11.6.0:*:*:*:*:*:*:*",
"range": [
{
"introduced": "11.6.0"
},
{
"last_affected": "11.6.0"
}
],
"source": "CPE_STRING"
}
]
}
}
],
"versions": [
"11.6.0",
"v11.5.3",
"v10.11.14",
"v11.4.4",
"v11.5.2-rc3",
"v11.5.2",
"v11.6.0",
"v10.11.14-rc1",
"v11.5.0",
"v11.5.2-rc2",
"v11.5.2-rc1",
"v11.4.3",
"v10.11.13",
"v11.5.1",
"v10.11.13-rc1",
"v11.4.2",
"v10.11.12",
"v11.4.1-rc2",
"v11.4.1-rc1",
"v11.4.1",
"v10.11.11-rc2",
"v10.11.11",
"v11.4.0-rc3",
"v11.4.0",
"mattermost-redux@11.4.0",
"@mattermost/types@11.4.0",
"@mattermost/client@11.4.0",
"v10.11.11-rc1",
"v10.11.10",
"v10.11.9",
"v10.11.9-rc1",
"v10.11.8",
"v10.11.7",
"v10.11.6",
"v10.11.5",
"v10.11.4-rc3",
"v10.11.4",
"v10.11.4-rc2",
"v10.11.4-rc1",
"v10.11.3",
"v10.11.2-rc2",
"v10.11.2",
"v10.11.2-rc1",
"v10.11.1",
"v10.11.1-rc1",
"v10.11.0-rc3",
"v10.11.0",
"mattermost-redux@10.11.0",
"@mattermost/types@10.11.0",
"@mattermost/client@10.11.0"
],
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-4858.json"
}
}
],
"modified": "2026-10-28T02:30:40.941289117Z",
"provider": "osv",
"references": [
"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/4xxx/CVE-2026-4858.json",
"https://mattermost.com/security-updates",
"https://nvd.nist.gov/vuln/detail/CVE-2026-4858"
],
"provider_metadata": {
"cwe_ids": [
"CWE-22"
],
"cna_assigner": "Mattermost",
"unresolved_ranges": [
{
"extracted_events": [
{
"range": [
{
"introduced": "11.6.0"
},
{
"last_affected": "11.6.0"
}
],
"source": "AFFECTED_FIELD",
"strategy": "StandaloneSingleVersion"
}
]
},
{
"extracted_events": [
{
"range": [
{
"introduced": "11.5.0"
},
{
"last_affected": "11.5.3"
},
{
"introduced": "11.4.0"
},
{
"last_affected": "11.4.4"
},
{
"introduced": "10.11.0"
},
{
"last_affected": "10.11.14"
}
],
"source": "AFFECTED_FIELD",
"strategy": "StandardRange"
}
]
}
],
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/4xxx/CVE-2026-4858.json"
}
},
"related_cves": [
{
"value": "CVE-2026-4858",
"evidence": "/id"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 508729,
"published_at": "2026-05-21T08:12:11.176+00:00"
}