CVE-2024-39830Network attack vector

Remote cluster token disclosure via timing comparison

Published Jul 3, 2024 · Updated Aug 2, 2024

Improper authentication in affected Mattermost releases allows remote attackers to retrieve remote cluster tokens through response timing. The remote-cluster token comparison uses a non-constant-time equality check, so response-time differences disclose information about successive token guesses. The unauthenticated network path is reachable only when shared channels and the remote-cluster service are enabled; token recovery compromises the trust credential used between connected servers.

CVSS severity8.1
High
EPSS probability0.38%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper authentication in affected Mattermost releases allows remote attackers to retrieve remote cluster tokens through response timing. The remote-cluster token comparison uses a non-constant-time equality check, so response-time differences disclose information about successive token guesses. The unauthenticated network path is reachable only when shared channels and the remote-cluster service are enabled; token recovery compromises the trust credential used between connected servers.

The record

CVE
CVE-2024-39830
Published
Jul 3, 2024
Updated
Aug 2, 2024
Vendor
Mattermost
Product
Mattermost
Classifications
CWE-287, CWE-203, T1528
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 3, 2024CVE publishedPublication date reported by the CVE source.
  2. Aug 2, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=9.5.0 <=9.5.5
  2. Affected versionversion=9.6.0 <=9.6.2
  3. Affected versionversion=9.7.0 <=9.7.4
  4. Affected versionversion=9.8.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Mattermost · Mattermostversion=9.5.0 <=9.5.5; version=9.6.0 <=9.6.2; version=9.7.0 <=9.7.4; version=9.8.0

Published CVSS scores

8.1Mattermost, Inc.CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
5.9NIST NVDCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-287Improper Authentication
CWE-203Observable Discrepancy
T1528Steal Application Access Token

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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