CVE-2024-11599Network attack vector

Unauthenticated domain bypass via multi-at-sign email

Published Nov 28, 2024 · Updated Nov 29, 2024

Improper email validation in affected Mattermost releases allows remote attackers to bypass signup domain restrictions during registration. The IsValidEmail function accepted addresses containing multiple at signs because mail.ParseAddress permits quoted address strings, causing domain checks to accept a misleading domain. Exploitation requires email signup, user creation, domain restriction, and email verification to be enabled; success creates an account outside the permitted domains.

CVSS severity8.2
High
EPSS probability0.47%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper email validation in affected Mattermost releases allows remote attackers to bypass signup domain restrictions during registration. The IsValidEmail function accepted addresses containing multiple at signs because mail.ParseAddress permits quoted address strings, causing domain checks to accept a misleading domain. Exploitation requires email signup, user creation, domain restriction, and email verification to be enabled; success creates an account outside the permitted domains.

The record

CVE
CVE-2024-11599
Published
Nov 28, 2024
Updated
Nov 29, 2024
Vendor
Mattermost
Product
Mattermost
Classifications
CWE-754, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 28, 2024CVE publishedPublication date reported by the CVE source.
  2. Nov 29, 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=10.0.0 <=10.0.1
  2. Affected versionversion=10.1.0 <=10.1.1
  3. Affected versionversion=9.11.0 <=9.11.3
  4. Affected versionversion=9.5.0 <=9.5.11

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Mattermost · Mattermostversion=10.0.0 <=10.0.1; version=10.1.0 <=10.1.1; version=9.11.0 <=9.11.3; version=9.5.0 <=9.5.11

Published CVSS scores

8.2Mattermost, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N
5.3NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-754Improper Check for Unusual or Exceptional Conditions
T1190Exploit Public-Facing Application

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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