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Vulnerability Details :

CVE-2026-3590

Summary
Assigner-Mattermost
Assigner Org ID-9302f53e-dde5-4bf3-b2f2-a83f91ac0eee
Published At-15 Apr, 2026 | 11:00
Updated At-15 Apr, 2026 | 14:00
Rejected At-
Credits

Race Condition in Guest Magic Link Authentication Allows Token Reuse

Mattermost versions 10.11.x <= 10.11.12, 11.5.x <= 11.5.0, 11.4.x <= 11.4.2, 11.3.x <= 11.3.2 fail to enforce atomic single-use consumption of guest magic link tokens, which allows an attacker with access to a valid magic link to establish multiple independent authenticated sessions via concurrent requests.. Mattermost Advisory ID: MMSA-2026-00624

Vendors
-
Not available
Products
-
Metrics (CVSS)
VersionBase scoreBase severityVector
Weaknesses
Attack Patterns
Solution/Workaround
References
HyperlinkResource Type
EPSS History
Score
Latest Score
-
N/A
No data available for selected date range
Percentile
Latest Percentile
-
N/A
No data available for selected date range
Stakeholder-Specific Vulnerability Categorization (SSVC)
▼Common Vulnerabilities and Exposures (CVE)
cve.org
Assigner:Mattermost
Assigner Org ID:9302f53e-dde5-4bf3-b2f2-a83f91ac0eee
Published At:15 Apr, 2026 | 11:00
Updated At:15 Apr, 2026 | 14:00
Rejected At:
▼CVE Numbering Authority (CNA)
Race Condition in Guest Magic Link Authentication Allows Token Reuse

Mattermost versions 10.11.x <= 10.11.12, 11.5.x <= 11.5.0, 11.4.x <= 11.4.2, 11.3.x <= 11.3.2 fail to enforce atomic single-use consumption of guest magic link tokens, which allows an attacker with access to a valid magic link to establish multiple independent authenticated sessions via concurrent requests.. Mattermost Advisory ID: MMSA-2026-00624

Affected Products
Vendor
Mattermost, Inc.Mattermost
Product
Mattermost
Default Status
unaffected
Versions
Affected
  • From 10.11.0 through 10.11.12 (semver)
  • From 11.5.0 through 11.5.0 (semver)
  • From 11.4.0 through 11.4.2 (semver)
  • From 11.3.0 through 11.3.2 (semver)
Unaffected
  • 11.6.0
  • 10.11.13
  • 11.5.1
  • 11.4.3
  • 11.3.3
Problem Types
TypeCWE IDDescription
CWECWE-367CWE-367: Time-of-check Time-of-use (TOCTOU) Race Condition
Type: CWE
CWE ID: CWE-367
Description: CWE-367: Time-of-check Time-of-use (TOCTOU) Race Condition
Metrics
VersionBase scoreBase severityVector
3.16.5MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
Version: 3.1
Base score: 6.5
Base severity: MEDIUM
Vector:
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
Metrics Other Info
Impacts
CAPEC IDDescription
Solutions

Update Mattermost to versions 11.6.0, 10.11.13, 11.5.1, 11.4.3, 11.3.3 or higher.

Configurations

Workarounds

Exploits

Credits

finder
Edgar Bellot Micó
Timeline
EventDate
Replaced By

Rejected Reason

References
HyperlinkResource
https://mattermost.com/security-updates
vendor-advisory
Hyperlink: https://mattermost.com/security-updates
Resource:
vendor-advisory
▼Authorized Data Publishers (ADP)
CISA ADP Vulnrichment
Affected Products
Metrics
VersionBase scoreBase severityVector
Metrics Other Info
Impacts
CAPEC IDDescription
Solutions

Configurations

Workarounds

Exploits

Credits

Timeline
EventDate
Replaced By

Rejected Reason

References
HyperlinkResource
Information is not available yet
▼National Vulnerability Database (NVD)
nvd.nist.gov
Source:responsibledisclosure@mattermost.com
Published At:15 Apr, 2026 | 12:16
Updated At:22 Apr, 2026 | 19:41

Mattermost versions 10.11.x <= 10.11.12, 11.5.x <= 11.5.0, 11.4.x <= 11.4.2, 11.3.x <= 11.3.2 fail to enforce atomic single-use consumption of guest magic link tokens, which allows an attacker with access to a valid magic link to establish multiple independent authenticated sessions via concurrent requests.. Mattermost Advisory ID: MMSA-2026-00624

CISA Catalog
Date AddedDue DateVulnerability NameRequired Action
N/A
Date Added: N/A
Due Date: N/A
Vulnerability Name: N/A
Required Action: N/A
Metrics
TypeVersionBase scoreBase severityVector
Secondary3.16.5MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
Type: Secondary
Version: 3.1
Base score: 6.5
Base severity: MEDIUM
Vector:
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
CPE Matches

Mattermost, Inc.
mattermost
>>mattermost_server>>Versions from 10.11.0(inclusive) to 10.11.13(exclusive)
cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*
Mattermost, Inc.
mattermost
>>mattermost_server>>Versions from 11.3.0(inclusive) to 11.3.3(exclusive)
cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*
Mattermost, Inc.
mattermost
>>mattermost_server>>Versions from 11.4.0(inclusive) to 11.4.3(exclusive)
cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*
Mattermost, Inc.
mattermost
>>mattermost_server>>Versions from 11.5.0(inclusive) to 11.5.1(exclusive)
cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*
Weaknesses
CWE IDTypeSource
CWE-367Secondaryresponsibledisclosure@mattermost.com
CWE ID: CWE-367
Type: Secondary
Source: responsibledisclosure@mattermost.com
Evaluator Description

Evaluator Impact

Evaluator Solution

Vendor Statements

References
HyperlinkSourceResource
https://mattermost.com/security-updatesresponsibledisclosure@mattermost.com
Vendor Advisory
Hyperlink: https://mattermost.com/security-updates
Source: responsibledisclosure@mattermost.com
Resource:
Vendor Advisory

Change History

0
Information is not available yet

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Details not found