CVE-2026-2454
Out-of-Memory Crash via Malformed Msgpack in Mattermost Websocket
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-1287 | The product receives input that is expected to be of a certain type, but it does not validate or incorrectly validates that the input is actually of the expected type. |
Attack-Flow Graph
AI Powered Q&A
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?
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What immediate steps should I take to mitigate this vulnerability?
I don't know
How can this vulnerability impact me? :
The impact of this vulnerability is that an attacker can cause the Mattermost server to crash by triggering out-of-memory errors. This results in a denial of service (DoS) condition, making the service unavailable to legitimate users.
Can you explain this vulnerability to me?
This vulnerability exists in certain versions of Mattermost (11.3.x <= 11.3.0, 11.2.x <= 11.2.2, 10.11.x <= 10.11.10) where the software fails to properly handle incorrectly reported array lengths. A malicious user can exploit this by sending corrupted msgpack frames within websocket messages to the calls plugin, which can cause out-of-memory (OOM) errors and crash the server.