Mattermost up to 10.11.19/11.6.4/11.7.2 OAuth Refresh Token Grant Endpoint privilege escalation

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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6.0$0-$5k1.56+

Summaryinfo

A vulnerability, which was classified as critical, has been found in Mattermost up to 10.11.19/11.6.4/11.7.2. This issue affects some unknown processing of the component OAuth Refresh Token Grant Endpoint. Performing a manipulation results in Remote Privilege Escalation. This vulnerability is identified as CVE-2026-9571. The attack can be initiated remotely. There is not any exploit available.

Detailsinfo

A vulnerability, which was classified as critical, was found in Mattermost up to 10.11.19/11.6.4/11.7.2. This affects an unknown functionality of the component OAuth Refresh Token Grant Endpoint. The manipulation with an unknown input leads to a remote privilege escalation vulnerability. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

Mattermost versions 11.7.x <= 11.7.2, 11.6.x <= 11.6.4, 10.11.x <= 10.11.19 fail to invalidate OAuth refresh tokens upon user account deactivation, which allows a deactivated user or an attacker in possession of a valid refresh token to obtain new functional access tokens via the OAuth refresh token grant endpoint.. Mattermost Advisory ID: MMSA-2026-00680

It is possible to read the advisory at mattermost.com. This vulnerability is uniquely identified as CVE-2026-9571 since 05/26/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. The technical details are unknown and an exploit is not publicly available.

Upgrading to version 10.11.20, 11.6.5, 11.7.3 or 11.8.0 eliminates this vulnerability.

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Type

Name

Version

License

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.3
VulDB Meta Temp Score: 6.0

VulDB Base Score: 6.3
VulDB Temp Score: 6.0
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

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

Exploitinginfo

Class: Privilege escalation
CWE: Unknown
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: no mitigation known
Status: 🔍

0-Day Time: 🔒

Upgrade: Mattermost 10.11.20/11.6.5/11.7.3/11.8.0

Timelineinfo

05/26/2026 CVE reserved
07/13/2026 +48 days Advisory disclosed
07/13/2026 +0 days VulDB entry created
07/13/2026 +0 days VulDB entry last update

Sourcesinfo

Advisory: mattermost.com
Status: Confirmed

CVE: CVE-2026-9571 (🔒)
GCVE (CVE): GCVE-0-2026-9571
GCVE (VulDB): GCVE-100-377931

Entryinfo

Created: 07/13/2026 11:12
Changes: 07/13/2026 11:12 (52)
Complete: 🔍
Cache ID: 216::103

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

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