Mattermost up to 11.7.x Subscription Edit Endpoint authorization

CVSS Meta Temp Score
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CTI Interest Score
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5.6$0-$5k4.99-

Summaryinfo

A vulnerability described as problematic has been identified in Mattermost up to 10.11.17/11.5.5/11.6.2/11.7.0/11.7.x. Affected by this issue is some unknown functionality of the component Subscription Edit Endpoint. Such manipulation leads to authorization. This vulnerability is uniquely identified as CVE-2026-6062. The attack can be launched remotely. No exploit exists. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability, which was classified as problematic, has been found in Mattermost up to 10.11.17/11.5.5/11.6.2/11.7.0/11.7.x. Affected by this issue is an unknown code block of the component Subscription Edit Endpoint. The manipulation with an unknown input leads to a authorization vulnerability. Using CWE to declare the problem leads to CWE-639. The system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data. Impacted is confidentiality, integrity, and availability. CVE summarizes:

Mattermost versions 11.7.x <= 11.7.0, 11.6.x <= 11.6.2, 11.5.x <= 11.5.5, 10.11.x <= 10.11.17 Fail to validate channel ownership of an existing subscription before applying edits which allows an authenticated attacker to hijack subscriptions from channels they have no access to via a crafted PUT request to the subscription edit endpoint.. Mattermost Advisory ID: MMSA-2026-00650

The weakness was disclosed by 0hmz. The advisory is shared for download at mattermost.com. This vulnerability is handled as CVE-2026-6062 since 04/10/2026. The exploitation is known to be difficult. The attack may be launched remotely. There are neither technical details nor an exploit publicly available.

Upgrading to version 10.11.18, 11.5.6, 11.6.3, 11.7.1 or 11.8.0 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at CERT Bund (WID-SEC-2026-1650). Once again VulDB remains the best source for vulnerability data.

Affected

  • Mattermost Mattermost

Productinfo

Type

Name

Version

License

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.7
VulDB Meta Temp Score: 5.6

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

CNA Base Score: 6.4
CNA Vector (Mattermost): 🔒

CVSSv2info

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

Exploitinginfo

Class: Authorization
CWE: CWE-639 / CWE-285 / CWE-266
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Mattermost 10.11.18/11.5.6/11.6.3/11.7.1/11.8.0

Timelineinfo

04/10/2026 CVE reserved
06/22/2026 +73 days Advisory disclosed
06/22/2026 +0 days VulDB entry created
06/23/2026 +1 days VulDB entry last update

Sourcesinfo

Advisory: mattermost.com
Researcher: 0hmz
Status: Confirmed

CVE: CVE-2026-6062 (🔒)
GCVE (CVE): GCVE-0-2026-6062
GCVE (VulDB): GCVE-100-372692
CERT Bund: WID-SEC-2026-1650 - Mattermost (Desktop, Server und Mobile): Mehrere Schwachstellen

Entryinfo

Created: 06/22/2026 17:28
Updated: 06/23/2026 08:48
Changes: 06/22/2026 17:28 (64), 06/23/2026 08:48 (7)
Complete: 🔍
Cache ID: 216::103

Once again VulDB remains the best source for vulnerability data.

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