CVE-2026-2456
Denial of Service via Memory Exhaustion in Mattermost Integrations
Publication date: 2026-03-16
Last updated on: 2026-03-18
Assigner: Mattermost, Inc.
Description
Description
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| mattermost | mattermost_server | From 10.11.0 (inc) to 10.11.11 (exc) |
| mattermost | mattermost_server | From 11.2.0 (inc) to 11.2.3 (exc) |
| mattermost | mattermost_server | From 11.3.0 (inc) to 11.3.1 (exc) |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-789 | The product allocates memory based on an untrusted, large size value, but it does not ensure that the size is within expected limits, allowing arbitrary amounts of memory to be allocated. |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
This vulnerability exists in Mattermost versions 11.3.x <= 11.3.0, 11.2.x <= 11.2.2, and 10.11.x <= 10.11.10. It occurs because Mattermost does not limit the size of responses from integration action endpoints.
An authenticated attacker can exploit this by using a malicious integration server that returns an arbitrarily large response when a user clicks an interactive message button.
This can cause the server to exhaust its memory, leading to a denial of service condition.
How can this vulnerability impact me? :
The primary impact of this vulnerability is a denial of service (DoS) on the Mattermost server.
An attacker who is authenticated can cause the server to consume excessive memory by sending large responses through a malicious integration, potentially making the service unavailable to legitimate users.
How does this vulnerability affect compliance with common standards and regulations (like GDPR, HIPAA)?:
I don't know
How can this vulnerability be detected on my network or system? Can you suggest some commands?
I don't know
What immediate steps should I take to mitigate this vulnerability?
I don't know