CVE-2023-35075Network attack vector

HTML injection via channel autocomplete

Published Nov 27, 2023 · Updated Jun 3, 2025

HTML injection in Mattermost 8.1.3 and earlier allows remote authenticated users to alter autocomplete displays with crafted channel names. The webapp sets the autocomplete channel name without using innerText or textContent, causing a valid HTML channel name to be interpreted as markup. Exploitation requires channel-creation access and a victim who encounters the name in autocomplete; script execution is not possible, limiting impact to displayed content.

CVSS severity3.1
Low
EPSS probability0.37%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

HTML injection in Mattermost 8.1.3 and earlier allows remote authenticated users to alter autocomplete displays with crafted channel names. The webapp sets the autocomplete channel name without using innerText or textContent, causing a valid HTML channel name to be interpreted as markup. Exploitation requires channel-creation access and a victim who encounters the name in autocomplete; script execution is not possible, limiting impact to displayed content.

The record

CVE
CVE-2023-35075
Published
Nov 27, 2023
Updated
Jun 3, 2025
Vendor
Mattermost
Product
Mattermost
Classifications
CWE-74
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Nov 27, 2023CVE publishedPublication date reported by the CVE source.
  2. Jun 3, 2025Record 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 <=7.8.12
  2. Affected versionversion=0 <=8.1.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Mattermost · Mattermostversion=0 <=7.8.12; version=0 <=8.1.3

Published CVSS scores

3.1Mattermost, Inc.CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N
5.4NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/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-74Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')

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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