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Vulnerability Details :

CVE-2026-2456

Summary
Assigner-Mattermost
Assigner Org ID-9302f53e-dde5-4bf3-b2f2-a83f91ac0eee
Published At-16 Mar, 2026 | 11:06
Updated At-16 Mar, 2026 | 13:49
Rejected At-
Credits

Denial of Service via Unbounded Memory Allocation in Integration Actions

Mattermost versions 11.3.x <= 11.3.0, 11.2.x <= 11.2.2, 10.11.x <= 10.11.10 Mattermost fails to limit the size of responses from integration action endpoints, which allows an authenticated attacker to cause server memory exhaustion and denial of service via a malicious integration server that returns an arbitrarily large response when a user clicks an interactive message button.. Mattermost Advisory ID: MMSA-2026-00571

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:16 Mar, 2026 | 11:06
Updated At:16 Mar, 2026 | 13:49
Rejected At:
▼CVE Numbering Authority (CNA)
Denial of Service via Unbounded Memory Allocation in Integration Actions

Mattermost versions 11.3.x <= 11.3.0, 11.2.x <= 11.2.2, 10.11.x <= 10.11.10 Mattermost fails to limit the size of responses from integration action endpoints, which allows an authenticated attacker to cause server memory exhaustion and denial of service via a malicious integration server that returns an arbitrarily large response when a user clicks an interactive message button.. Mattermost Advisory ID: MMSA-2026-00571

Affected Products
Vendor
Mattermost, Inc.Mattermost
Product
Mattermost
Default Status
unaffected
Versions
Affected
  • From 11.3.0 through 11.3.0 (semver)
  • From 11.2.0 through 11.2.2 (semver)
  • From 10.11.0 through 10.11.10 (semver)
Unaffected
  • 11.4.0
  • 11.3.1
  • 11.2.3
  • 10.11.11
Problem Types
TypeCWE IDDescription
CWECWE-789CWE-789: Memory Allocation with Excessive Size Value
Type: CWE
CWE ID: CWE-789
Description: CWE-789: Memory Allocation with Excessive Size Value
Metrics
VersionBase scoreBase severityVector
3.15.3MEDIUM
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:H
Version: 3.1
Base score: 5.3
Base severity: MEDIUM
Vector:
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:H
Metrics Other Info
Impacts
CAPEC IDDescription
Solutions

Update Mattermost to versions 11.4.0, 11.3.1, 11.2.3, 10.11.11 or higher.

Configurations
Workarounds
Exploits
Credits
finder
Daniel Espino Garcia
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:16 Mar, 2026 | 14:19
Updated At:18 Mar, 2026 | 18:27

Mattermost versions 11.3.x <= 11.3.0, 11.2.x <= 11.2.2, 10.11.x <= 10.11.10 Mattermost fails to limit the size of responses from integration action endpoints, which allows an authenticated attacker to cause server memory exhaustion and denial of service via a malicious integration server that returns an arbitrarily large response when a user clicks an interactive message button.. Mattermost Advisory ID: MMSA-2026-00571

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
Secondary3.15.3MEDIUM
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:H
Primary3.15.7MEDIUM
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:H
Type: Secondary
Version: 3.1
Base score: 5.3
Base severity: MEDIUM
Vector:
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:H
Type: Primary
Version: 3.1
Base score: 5.7
Base severity: MEDIUM
Vector:
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:H
CPE Matches
Mattermost, Inc.
mattermost
>>mattermost_server>>Versions from 10.11.0(inclusive) to 10.11.11(exclusive)
cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*
Mattermost, Inc.
mattermost
>>mattermost_server>>Versions from 11.2.0(inclusive) to 11.2.3(exclusive)
cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*
Mattermost, Inc.
mattermost
>>mattermost_server>>Versions from 11.3.0(inclusive) to 11.3.1(exclusive)
cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*
Weaknesses
CWE IDTypeSource
CWE-789Secondaryresponsibledisclosure@mattermost.com
CWE ID: CWE-789
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