Mattermost up to 10.11.13/11.4.3/11.5.1/11.5.x insufficiently protected credentials

CVSS Meta Temp Score
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CTI Interest Score
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4.5$0-$5k0.00

Summaryinfo

A vulnerability was found in Mattermost up to 10.11.13/11.4.3/11.5.1/11.5.x. It has been rated as problematic. This vulnerability affects unknown code. Performing a manipulation results in insufficiently protected credentials. This vulnerability is known as CVE-2026-6345. Remote exploitation of the attack is possible. No exploit is available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability classified as problematic has been found in Mattermost up to 10.11.13/11.4.3/11.5.1/11.5.x. This affects an unknown function. The manipulation with an unknown input leads to a insufficiently protected credentials vulnerability. CWE is classifying the issue as CWE-522. The product transmits or stores authentication credentials, but it uses an insecure method that is susceptible to unauthorized interception and/or retrieval. This is going to have an impact on confidentiality. The summary by CVE is:

Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13, 11.4.x <= 11.4.3 fail prevent disclosure of created user password which allows a malicious attacker to impersonate a user via the use of some of those passwords.. Mattermost Advisory ID: MMSA-2026-00614

The weakness was published by eeshan. It is possible to read the advisory at mattermost.com. This vulnerability is uniquely identified as CVE-2026-6345 since 04/15/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. The exploitation requires an enhanced level of successful authentication. The technical details are unknown and an exploit is not publicly available. The attack technique deployed by this issue is T1552 according to MITRE ATT&CK.

The vulnerability scanner Nessus provides a plugin with the ID 316492 (Mattermost Server 10.11.x <= 10.11.13 / 11.4.x <= 11.4.3 / 11.5.x <= 11.5.1 Multiple Vulnerabilities (MMSA-2026-00573 / MMSA-2026-00576 / MMSA-2026-00591 / MMSA-2026-00605 / MMSA-2026-00607 / MMSA-2026-00608 / MMSA-2026-00614 / MMSA-2026-00627)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 10.11.14, 11.4.4, 11.5.2 or 11.6.0 eliminates this vulnerability.

The vulnerability is also documented in the databases at Tenable (316492) and EUVD (EUVD-2026-30756). Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

Type

Name

Version

License

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 4.6
VulDB Meta Temp Score: 4.5

VulDB Base Score: 2.7
VulDB Temp Score: 2.6
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 6.5
CNA Vector (Mattermost): 🔒

CVSSv2info

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

Exploitinginfo

Class: Insufficiently protected credentials
CWE: CWE-522
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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Nessus ID: 316492
Nessus Name: Mattermost Server 10.11.x <= 10.11.13 / 11.4.x <= 11.4.3 / 11.5.x <= 11.5.1 Multiple Vulnerabilities (MMSA-2026-00573 / MMSA-2026-00576 / MMSA-2026-00591 / MMSA-2026-00605 / MMSA-2026-00607 / MMSA-2026-00608 / MMSA-2026-00614 / MMSA-2026-00627)

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Mattermost 10.11.14/11.4.4/11.5.2/11.6.0

Timelineinfo

04/15/2026 CVE reserved
05/18/2026 +33 days Advisory disclosed
05/18/2026 +0 days VulDB entry created
05/23/2026 +5 days VulDB entry last update

Sourcesinfo

Advisory: mattermost.com
Researcher: eeshan
Status: Confirmed

CVE: CVE-2026-6345 (🔒)
GCVE (CVE): GCVE-0-2026-6345
GCVE (VulDB): GCVE-100-364455
EUVD: 🔒

Entryinfo

Created: 05/18/2026 12:24
Updated: 05/23/2026 11:11
Changes: 05/18/2026 12:24 (63), 05/18/2026 15:34 (1), 05/23/2026 11:11 (2)
Complete: 🔍
Cache ID: 216::103

Be aware that VulDB is the high quality source for vulnerability data.

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