CVE-2024-47003Network attack vector

Client crash via unsanitized WebSocket embed metadata

Published Sep 26, 2024 · Updated Sep 26, 2024

Improper input validation in Mattermost 9.11.0 and 9.5.0 through 9.5.8 allows remote authenticated users to crash clients via posts. The post broadcast path fails to remove user-supplied embeds from metadata before sending posted events over WebSockets, so a permalink embed can carry a non-string message into frontend handling. A valid account must create the crafted post; affected clients processing the broadcast can crash, while the server remains available.

CVSS severity3.1
Low
EPSS probability0.58%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper input validation in Mattermost 9.11.0 and 9.5.0 through 9.5.8 allows remote authenticated users to crash clients via posts. The post broadcast path fails to remove user-supplied embeds from metadata before sending posted events over WebSockets, so a permalink embed can carry a non-string message into frontend handling. A valid account must create the crafted post; affected clients processing the broadcast can crash, while the server remains available.

The record

CVE
CVE-2024-47003
Published
Sep 26, 2024
Updated
Sep 26, 2024
Vendor
Mattermost
Product
Mattermost
Classifications
CWE-400, T1499
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 26, 2024CVE publishedPublication date reported by the CVE source.
  2. Sep 26, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=9.11.0
  2. Affected versionversion=9.5.0 <=9.5.8

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Mattermost · Mattermostversion=9.11.0; version=9.5.0 <=9.5.8

Published CVSS scores

5.3GitHub Advisory DatabaseCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N
6.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
3.1MattermostCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L

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.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-400Uncontrolled Resource Consumption
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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