CVE-2023-5876Network attack vector

Client denial of service via unvalidated path regex

Published Nov 2, 2023 · Updated Sep 5, 2024

Resource consumption in Mattermost Desktop 5.5.0 and earlier allows remote attackers to interrupt the client via a crafted server URL path. The desktop client constructs a regular expression from the server URL path without sufficient validation, permitting excessive regex processing. Exploitation requires control of a server already enrolled in the desktop app, and the reported consequence is limited to client availability.

CVSS severity5.3
Medium
EPSS probability0.49%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Resource consumption in Mattermost Desktop 5.5.0 and earlier allows remote attackers to interrupt the client via a crafted server URL path. The desktop client constructs a regular expression from the server URL path without sufficient validation, permitting excessive regex processing. Exploitation requires control of a server already enrolled in the desktop app, and the reported consequence is limited to client availability.

The record

CVE
CVE-2023-5876
Published
Nov 2, 2023
Updated
Sep 5, 2024
Vendor
Mattermost
Product
Mattermost Desktop
Classifications
CWE-400, T1499.004
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Nov 2, 2023CVE publishedPublication date reported by the CVE source.
  2. Sep 5, 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=0 <=5.5.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Mattermost · Mattermost Desktopversion=0 <=5.5.0

Published CVSS scores

5.3NVDCVSS:3.1/AV:N/AC:H/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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 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
T1499.004Application or System Exploitation

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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