CVE-2023-36556Network attack vector

Cross-account access via incorrect webmail authorization

Published Oct 10, 2023 · Updated Dec 16, 2025

Incorrect authorization in Fortinet FortiMail webmail allows remote authenticated users to access other accounts through crafted HTTP requests. Fortinet has not disclosed which webmail endpoint or parameter fails to enforce account ownership when processing the crafted request. An attacker needs a valid account in the same web domain; successful exploitation grants access to another user's mailbox and account capabilities.

CVSS severity8.8
High
EPSS probability0.84%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Incorrect authorization in Fortinet FortiMail webmail allows remote authenticated users to access other accounts through crafted HTTP requests. Fortinet has not disclosed which webmail endpoint or parameter fails to enforce account ownership when processing the crafted request. An attacker needs a valid account in the same web domain; successful exploitation grants access to another user's mailbox and account capabilities.

The record

CVE
CVE-2023-36556
Published
Oct 10, 2023
Updated
Dec 16, 2025
Vendor
Fortinet
Product
FortiMail
Classifications
CWE-863, T1190
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Oct 10, 2023CVE publishedPublication date reported by the CVE source.
  2. Dec 16, 2025Record 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=6.0.0 <=6.0.12
  2. Affected versionversion=6.2.0 <=6.2.9
  3. Affected versionversion=6.4.0 <=6.4.7
  4. Affected versionversion=7.0.0 <=7.0.5
  5. Affected versionversion=7.2.0 <=7.2.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Fortinet · FortiMailversion=6.0.0 <=6.0.12; version=6.2.0 <=6.2.9; version=6.4.0 <=6.4.7; version=7.0.0 <=7.0.5; version=7.2.0 <=7.2.2

Published CVSS scores

8.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
8.8Fortinet, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-863Incorrect Authorization
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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