CVE-2017-18907Network attack vector

Browser-context script execution via channel headers

Published Jun 19, 2020 · Updated Aug 5, 2024

Cross-site scripting in Mattermost Server before 3.9.2 and 3.10.0 through 3.10.1 allows remote attackers to execute script via channel headers. The public record identifies channel-header content as the input but does not disclose the rendering path or the missing neutralization step. A user must view the affected header, allowing script to execute in that user's browser context.

CVSS severity6.1
Medium
EPSS probability0.69%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cross-site scripting in Mattermost Server before 3.9.2 and 3.10.0 through 3.10.1 allows remote attackers to execute script via channel headers. The public record identifies channel-header content as the input but does not disclose the rendering path or the missing neutralization step. A user must view the affected header, allowing script to execute in that user's browser context.

The record

CVE
CVE-2017-18907
Published
Jun 19, 2020
Updated
Aug 5, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-79, T1059.007
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

6.1GitHub Advisory DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
4.3NIST National Vulnerability DatabaseAV:N/AC:M/Au:N/C:N/I:P/A:N
6.1NIST National Vulnerability DatabaseCVSS:3.1/AV:N/AC:L/PR:N/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1059.007JavaScript/JScript

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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