Server crash via malformed msgpack array lengths
Published Mar 16, 2026 · Updated Mar 16, 2026
Denial of service in Mattermost 10.11.0 through 10.11.10, 11.2.0 through 11.2.2, and 11.3.0 allows remote attackers to crash the server. The Calls plugin trusts an incorrectly reported msgpack array length in corrupted frames carried inside WebSocket messages, causing memory exhaustion. Network access to the Calls WebSocket endpoint is sufficient; the resulting out-of-memory condition terminates the server without reported data disclosure or modification.
Summary
What happened
Denial of service in Mattermost 10.11.0 through 10.11.10, 11.2.0 through 11.2.2, and 11.3.0 allows remote attackers to crash the server. The Calls plugin trusts an incorrectly reported msgpack array length in corrupted frames carried inside WebSocket messages, causing memory exhaustion. Network access to the Calls WebSocket endpoint is sufficient; the resulting out-of-memory condition terminates the server without reported data disclosure or modification.
The record
- CVE
- CVE-2026-2454
- Published
- Mar 16, 2026
- Updated
- Mar 16, 2026
- Vendor
- Mattermost
- Product
- Mattermost
- Classifications
- CWE-1287, T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Mar 16, 2026CVE publishedPublication date reported by the CVE source.
- Mar 16, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=10.11.0 <=10.11.10
- Affected versionversion=11.2.0 <=11.2.2
- Affected versionversion=11.3.0 <=11.3.0
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
Check the software in your environment
Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.
Book a demo