CVE-2019-20858Network attack vector

Unauthenticated CPU exhaustion via crafted LIKE characters

Published Jun 19, 2020 · Updated Aug 5, 2024

Resource exhaustion in Mattermost Server before 5.15.0 allows remote attackers to consume server CPU through a crafted APIv4 request. The affected APIv4 endpoint places attacker-controlled characters in a SQL LIKE clause whose evaluation consumes excessive CPU. No authentication or user interaction is required, and successful requests can interrupt service without reported data exposure or modification.

CVSS severity7.5
High
EPSS probability1.11%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Resource exhaustion in Mattermost Server before 5.15.0 allows remote attackers to consume server CPU through a crafted APIv4 request. The affected APIv4 endpoint places attacker-controlled characters in a SQL LIKE clause whose evaluation consumes excessive CPU. No authentication or user interaction is required, and successful requests can interrupt service without reported data exposure or modification.

The record

CVE
CVE-2019-20858
Published
Jun 19, 2020
Updated
Aug 5, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-400, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 19, 2020CVE publishedPublication date reported by the CVE source.
  2. Aug 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

5.0NIST NVDAV:N/AC:L/Au:N/C:N/I:N/A:P
7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

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
Privilegesunauthenticated
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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