Mattermost up to 10.5.11/10.11.3/10.12.0 MSTeams Plugin missing authentication

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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5.3$0-$5k0.00

Summaryinfo

A vulnerability has been found in Mattermost up to 10.5.11/10.11.3/10.12.0 and classified as critical. This affects an unknown function of the component MSTeams Plugin Handler. This manipulation causes missing authentication. This vulnerability is handled as CVE-2025-55073. The attack can be initiated remotely. There is not any exploit available. The affected component should be upgraded.

Detailsinfo

A vulnerability classified as critical was found in Mattermost up to 10.5.11/10.11.3/10.12.0. Affected by this vulnerability is an unknown part of the component MSTeams Plugin Handler. The manipulation with an unknown input leads to a missing authentication vulnerability. The CWE definition for the vulnerability is CWE-306. The product does not perform any authentication for functionality that requires a provable user identity or consumes a significant amount of resources. As an impact it is known to affect integrity, and availability. The summary by CVE is:

Mattermost versions 10.11.x <= 10.11.3, 10.5.x <= 10.5.11, 10.12.x <= 10.12.0 fail to validate the relationship between the post being updated and the MSTeams plugin OAuth flow which allows an attacker to edit arbitrary posts via a crafted MSTeams plugin OAuth redirect URL.

The weakness was released by Juho Forsén. The advisory is shared at mattermost.com. This vulnerability is known as CVE-2025-55073 since 10/15/2025. The exploitation appears to be easy. The attack can be launched remotely. Neither technical details nor an exploit are publicly available.

Upgrading to version 10.5.12, 10.11.4, 10.12.1 or 11.0.0 eliminates this vulnerability.

The vulnerability is also documented in the databases at EUVD (EUVD-2025-186555) and CERT Bund (WID-SEC-2025-2315). If you want to get the best quality for vulnerability data then you always have to consider 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: 5.4
VulDB Meta Temp Score: 5.3

VulDB Base Score: 5.4
VulDB Temp Score: 5.2
VulDB Vector: 🔒
VulDB Reliability: 🔍

NVD Base Score: 5.3
NVD Vector: 🔒

CNA Base Score: 5.4
CNA Vector (Mattermost): 🔒

CVSSv2info

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

Exploitinginfo

Class: Missing authentication
CWE: CWE-306 / CWE-287
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

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 10.5.12/10.11.4/10.12.1/11.0.0

Timelineinfo

10/15/2025 CVE reserved
11/14/2025 +30 days Advisory disclosed
11/14/2025 +0 days VulDB entry created
11/28/2025 +14 days VulDB entry last update

Sourcesinfo

Advisory: mattermost.com
Researcher: Juho Forsén
Status: Confirmed

CVE: CVE-2025-55073 (🔒)
GCVE (CVE): GCVE-0-2025-55073
GCVE (VulDB): GCVE-100-332461
EUVD: 🔒
CERT Bund: WID-SEC-2025-2315 - Mattermost Server und Mobile: Mehrere Schwachstellen

Entryinfo

Created: 11/14/2025 11:10
Updated: 11/28/2025 16:14
Changes: 11/14/2025 11:10 (65), 11/14/2025 16:29 (1), 11/19/2025 02:02 (7), 11/20/2025 07:19 (9), 11/28/2025 16:14 (1)
Complete: 🔍
Cache ID: 216::103

If you want to get the best quality for vulnerability data then you always have to consider VulDB.

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