CVE-2018-21250Network attack vector

Service crash via crafted image dimensions

Published Jun 19, 2020 · Updated Aug 5, 2024

Resource exhaustion in Mattermost Server before 5.2.2, 5.1.2, and 4.10.4 allows remote attackers to crash the service via an image. The HandleImages path invokes generateThumbnailImage and generatePreviewImage on dimensions that drive memory allocation without an effective resolution bound. A user must cause server-side attachment processing; successful exploitation exhausts memory and terminates the Mattermost process.

CVSS severity6.5
Medium
EPSS probability1.08%
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 5.2.2, 5.1.2, and 4.10.4 allows remote attackers to crash the service via an image. The HandleImages path invokes generateThumbnailImage and generatePreviewImage on dimensions that drive memory allocation without an effective resolution bound. A user must cause server-side attachment processing; successful exploitation exhausts memory and terminates the Mattermost process.

The record

CVE
CVE-2018-21250
Published
Jun 19, 2020
Updated
Aug 5, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-400, T1499.004
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

6.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
4.3NIST NVDAV:N/AC:M/Au:N/C:N/I:N/A:P

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
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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