CVE-2023-4105Network attack vector

Deleted attachment disclosure via incomplete thread cleanup

Published Aug 11, 2023 · Updated Oct 1, 2024

Missing authorization in Mattermost 7.8.7, 7.9.5, and 7.10.3 and earlier allows remote authenticated users to download deleted attachments. The threaded-message deletion path removes the message without revoking access to its attached files, leaving their download references usable. Remote authenticated users can retrieve a retained attachment after its parent message is deleted, exposing the file contents.

CVSS severity3.1
Low
EPSS probability0.40%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Missing authorization in Mattermost 7.8.7, 7.9.5, and 7.10.3 and earlier allows remote authenticated users to download deleted attachments. The threaded-message deletion path removes the message without revoking access to its attached files, leaving their download references usable. Remote authenticated users can retrieve a retained attachment after its parent message is deleted, exposing the file contents.

The record

CVE
CVE-2023-4105
Published
Aug 11, 2023
Updated
Oct 1, 2024
Vendor
Mattermost
Product
Mattermost
Classifications
CWE-862, T1213.005
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 11, 2023CVE publishedPublication date reported by the CVE source.
  2. Oct 1, 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 <=7.10.3
  2. Affected versionversion=0 <=7.8.7
  3. Affected versionversion=0 <=7.9.5

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Mattermost · Mattermostversion=0 <=7.10.3; version=0 <=7.8.7; version=0 <=7.9.5

Published CVSS scores

4.3NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
3.1Mattermost, Inc.CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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-862Missing Authorization
T1213.005Messaging Applications

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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