CVE-2017-18874Network attack vector

Administrator file placement via unsanitized upload identifiers

Published Jun 19, 2020 · Updated Aug 5, 2024

Path traversal in Mattermost Server before 4.3.0, 4.2.1, and 4.1.2 allows remote authenticated users to write files outside local storage. The upload path builder used raw team, channel, and user identifiers as path components, while channel authorization fell back to a broad permission when lookup failed. A System Admin must submit crafted ../../ identifiers while local file storage is enabled, enabling attacker-controlled files to be placed outside the intended storage tree.

CVSS severity6.5
Medium
EPSS probability1.23%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Path traversal in Mattermost Server before 4.3.0, 4.2.1, and 4.1.2 allows remote authenticated users to write files outside local storage. The upload path builder used raw team, channel, and user identifiers as path components, while channel authorization fell back to a broad permission when lookup failed. A System Admin must submit crafted ../../ identifiers while local file storage is enabled, enabling attacker-controlled files to be placed outside the intended storage tree.

The record

CVE
CVE-2017-18874
Published
Jun 19, 2020
Updated
Aug 5, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-22
Attack vector
network
Privileges
admin

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 privilegesadmin

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

5.5NIST NVDAV:N/AC:L/Au:S/C:P/I:P/A:N
6.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N

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
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-22Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

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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