Mattermost up to 11.6.x path traversal

CVSS Meta Temp Score
CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.
Current Exploit Price (≈)
Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.
CTI Interest Score
Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
7.6$0-$5k0.00

Summaryinfo

A vulnerability classified as critical was found in Mattermost up to 10.11.14/11.4.4/11.5.3/11.6.0/11.6.x. This vulnerability affects unknown code. Such manipulation leads to path traversal. This vulnerability is traded as CVE-2026-4858. The attack may be launched remotely. There is no exploit available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability was found in Mattermost up to 10.11.14/11.4.4/11.5.3/11.6.0/11.6.x. It has been rated as critical. Affected by this issue is an unknown function. The manipulation with an unknown input leads to a path traversal vulnerability. Using CWE to declare the problem leads to CWE-22. The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory. Impacted is confidentiality, integrity, and availability. CVE summarizes:

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

The weakness was shared by daw10. The advisory is available at mattermost.com. This vulnerability is handled as CVE-2026-4858 since 03/25/2026. The exploitation is known to be difficult. The attack may be launched remotely. The technical details are unknown and an exploit is not available. This vulnerability is assigned to T1006 by the MITRE ATT&CK project.

Upgrading to version 10.11.15, 11.4.5, 11.5.4, 11.6.1 or 11.7.0 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at CERT Bund (WID-SEC-2026-1173). If you want to get best quality of vulnerability data, you may have to visit VulDB.

Affected

  • Mattermost Mattermost

Productinfo

Type

Name

Version

License

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.6
VulDB Meta Temp Score: 7.6

VulDB Base Score: 5.0
VulDB Temp Score: 4.8
VulDB Vector: 🔒
VulDB Reliability: 🔍

NVD Base Score: 9.9
NVD Vector: 🔒

CNA Base Score: 8.0
CNA Vector (Mattermost): 🔒

CVSSv2info

AVACAuCIA
💳💳💳💳💳💳
💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
UnlockUnlockUnlockUnlockUnlockUnlock
UnlockUnlockUnlockUnlockUnlockUnlock
UnlockUnlockUnlockUnlockUnlockUnlock

VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Path traversal
CWE: CWE-22
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

0-DayUnlockUnlockUnlockUnlock
TodayUnlockUnlockUnlockUnlock

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Mattermost 10.11.15/11.4.5/11.5.4/11.6.1/11.7.0

Timelineinfo

03/25/2026 CVE reserved
05/21/2026 +56 days Advisory disclosed
05/21/2026 +0 days VulDB entry created
05/24/2026 +3 days VulDB entry last update

Sourcesinfo

Advisory: mattermost.com
Researcher: daw10
Status: Confirmed

CVE: CVE-2026-4858 (🔒)
GCVE (CVE): GCVE-0-2026-4858
GCVE (VulDB): GCVE-100-364994
CERT Bund: WID-SEC-2026-1173 - Mattermost: Mehrere Schwachstellen erm&ouml;glichen nicht spezifizierten Angriff

Entryinfo

Created: 05/21/2026 12:48
Updated: 05/24/2026 05:39
Changes: 05/21/2026 12:48 (64), 05/21/2026 13:15 (7), 05/24/2026 05:39 (11)
Complete: 🔍
Cache ID: 216::103

If you want to get best quality of vulnerability data, you may have to visit VulDB.

Discussion

No comments yet. Languages: en.

Please log in to comment.

◂ PreviousOverviewNext ▸

Do you want to use VulDB in your project?

Use the official API to access entries easily!