CVE-2026-6961

highpriority · track · 0EPSS 0.005 · 38 %ileDEEUUS

grimoire priorityP2 · Scheduled

Exploitable?

—

no known exploitation

Likely / severe?

0.45% (38th) EPSS

CVSS 7.6 · high

Is it mine?

24 products

Check your exposure

Who says so?

5 sources

cnnvd · enisa_euvd · osv · cert_bund

EPSS · scored 2026-10-23

Mattermost versions 11.6.x <= 11.6.1, 11.5.x <= 11.5.4, 10.11.x <= 10.11.15, 10.11.x <= 10.11.16 Mattermost fails to sanitize FileInfo.Name received from federated peers during shared channel file sync, which allows an attacker who controls a federated server to write files to arbitrary locations within the target server's filestore via path traversal sequences in the filename field.. Mattermost Advisory ID: MMSA-2026-00661

cvss

Technical severity, 0–10. One row per scoring source.

7.6

010

base score 0–10 · higher = more severe · hover a vector to decode

v3.17.6highCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:N/I:H/A:Lsecondary · ENISA EU

v3.17.6highCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:N/I:H/A:Lsecondary · responsibledisclosure@mattermost.comexploitability 2.3 · impact 4.7

v3.17.6highCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:N/I:H/A:Lsecondary · OSV

v3.17highCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:N/I:H/A:L/E:Usecondary · CVSS-BT (t0sche)

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Exploitation: none · Automatable: no · Technical Impact: totalcoordinatorcisa_ssvcUS

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-22USCWE-22US

affected products (24)

Products and version ranges known to be affected.

Mattermost Mattermost Server <10.11.17all versionscert_bundDE
Mattermost Mattermost Server <11.5.5all versionscert_bundDE
Mattermost Mattermost Server <11.6.2all versionscert_bundDE
Mattermost Mattermost Server <11.7.0all versionscert_bundDE
Mattermost Mattermost≤ Server <10.11.17cert_bundDE
Mattermost Mattermost≤ Server <11.5.5cert_bundDE
Mattermost Mattermost≤ Server <11.6.2cert_bundDE
Mattermost Mattermost≤ Server <11.7.0cert_bundDE
Mattermost Mattermost≤ 11.5.0 ≤11.5.4enisa_euvdEU
Mattermost Mattermost≤ 11.6.0 ≤11.6.1enisa_euvdEU
Mattermost Mattermost≤ 10.11.0 ≤10.11.16enisa_euvdEU
Mattermost Mattermost≤ 10.11.0 ≤10.11.15enisa_euvdEU
mattermost mattermost server10.11.0 → 10.11.17nvdUScpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*
mattermost mattermost server11.5.0 → 11.5.5nvdUScpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*
mattermost mattermost server11.6.0 → 11.6.2nvdUScpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*
Go github.com/mattermost/mattermost-server10.11.0 → 10.11.17osvUSpkg:golang/github.com/mattermost/mattermost-server
Go github.com/mattermost/mattermost-server10.11.0+incompatible → 10.11.17+incompatibleosvUSpkg:golang/github.com/mattermost/mattermost-server
Go github.com/mattermost/mattermost-server11.5.0 → 11.5.5osvUSpkg:golang/github.com/mattermost/mattermost-server
Go github.com/mattermost/mattermost-server11.5.0+incompatible → 11.5.5+incompatibleosvUSpkg:golang/github.com/mattermost/mattermost-server
Go github.com/mattermost/mattermost-server11.6.0 → 11.6.1osvUSpkg:golang/github.com/mattermost/mattermost-server

showing 20 of 24

advisories (3)

Vendor and ecosystem advisories describing this.

WID-SEC-W-2026-1529Mattermost Server: Mehrere Schwachstellen ermöglichen nicht spezifizierten AngriffDeutsch2026-05-14csaf · cert_bundDE
Ein entfernter, anonymer Angreifer kann mehrere Schwachstellen in Mattermost Server ausnutzen, um einen nicht näher spezifizierten Angriff durchzuführen.
GHSA-8qq9-cqj8-82w4Mattermost doesn't sanitize FileInfo.Name received from federated peers during shared channel file sync2026-06-12ghsa · osvUS
Mattermost versions 11.6.x <= 11.6.1, 11.5.x <= 11.5.4, 10.11.x <= 10.11.15, 10.11.x <= 10.11.16 fail to sanitize FileInfo.Name received from federated peers during shared channel file sync, which allows an attacker who controls a federated server to write files to arbitrary locations within the target server's filestore via path traversal sequences in the filename field. Mattermost Advisory ID: MMSA-2026-00661
GO-2026-6281Mattermost doesn't sanitize FileInfo.Name received from federated peers during shared channel file sync in github.com/mattermost/mattermost-server2026-08-25vendor · osvUS
Mattermost doesn't sanitize FileInfo.Name received from federated peers during shared channel file sync in github.com/mattermost/mattermost-server

also known as (5)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd osv cert_bund nvd NVD CVE.org MITRE

published 2026-06-12modified 2026-06-18

references (3)

External citations — patches, advisories, analysis.

scry

Attackers weaponise vulnerabilities like this against internet-exposed services. See what is exposed on your perimeter with a free passive scan.

Free scan