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A integer overflow or wraparound vulnerability in Fortinet FortiMail 8.0.0 through 8.0.1, FortiMail 7.6.0 through 7.6.6, FortiMail 7.4.0…

Affects FortiMail smtpd in 8.0.0-8.0.1, 7.6.0-7.6.6, 7.4.0-7.4.8, 7.2.0-7.2.9 and 7.0.0-7.0.9. Fixed in 8.0.2 or above.

CVE-2026-126149EUVD-2026-123822

Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.

7.5HighCNA
Exploited
No known exploitation
Fix
Fixed in 8.0.2
Who is exposed
Not reported

Do first: Upgrade to a fixed version: 8.0.2.

Published
Last modified
Reference
Last checked
39/100 · provisional
Unclear
None on Exploit-DB, Metasploit or GitHub
On X
View the cve.now post

Summary

A remote attacker who does not need to log in can crash a daemon in Fortinet FortiMail by triggering an integer overflow over the network. The flaw affects multiple FortiMail release lines, and the advisory gives no further detail on what the attacker can gain beyond the crash.

Read the original description

A integer overflow or wraparound vulnerability in Fortinet FortiMail 8.0.0 through 8.0.1, FortiMail 7.6.0 through 7.6.6, FortiMail 7.4.0 through 7.4.8, FortiMail 7.2 all versions may allow a remote unauthenticated attacker to crash the daemon.

Who should check

Teams running Fortinet FortiMail 8.0.0-8.0.1, 7.6.0-7.6.6, 7.4.0-7.4.8, or any 7.2 or 7.0 release, including mail gateway operators

Read the source excerpt

“An integer Overflow or Wraparound [CWE-190] in FortiMail smtpd may allow”

fortiguard.fortinet.com

cve.now Index

39Pcve.now Index 39 of 100 · methodology v3 · provisional
  • Exploitation?/40Unknown. No CISA SSVC exploitation rating yet
  • Exposure17/25No login or user action needed, reachable over the network without a login · Unknown: Advisories don't say whether default setups are affected
  • Reach14/20Affects Fortinet (an enterprise product or network appliance)
  • Severity7.5/10CVSS 7.5
  • No patch0/5No signal

What would change the score

  • Would score about 84 if added to CISA KEV
  • Would score about 79 if CISA's SSVC rates exploitation active
  • Would score about 44 if advisories confirm default setups are exposed

What to do

  • Upgrade to a fixed version: 8.0.2.

Check your systems with an agent

Paste this into a coding or ops agent. It checks your systems read-only and reports a table per asset.

Check whether my systems are affected by CVE-2026-126149 (A integer overflow or wraparound vulnerability in Fortinet FortiMail 8.0.0 through 8.0.1, FortiMail 7.6.0 through 7.6.6, FortiMail 7.4.0…), using the cve.now data below.

Rules: work read-only. Do not run exploit code, proof-of-concept scripts or scanners that send attack payloads, and do not change any configuration, package, image or deployment. Report findings only.

What cve.now has for CVE-2026-126149 (entry last updated 2026-11-11):
Affected:
- Fortinet FortiMail: from 8.0.0, through 8.0.1; from 7.6.0, through 7.6.6; from 7.4.0, through 7.4.8; from 7.2.0, through 7.2.9; from 7.0.0, through 7.0.9
Fixed versions: 8.0.2.
Conditions (all must be true for the bug to be hit):
- Affects the FortiMail smtpd component (source: https://fortiguard.fortinet.com/psirt/FG-IR-26-201)
- Affected FortiMail versions include 7.2 and 7.0 (all versions), plus 8.0.0-8.0.1, 7.6.0-7.6.6 and 7.4.0-7.4.8 (source: https://fortiguard.fortinet.com/psirt/FG-IR-26-201)
Setup: unknown whether the bug needs a non-default feature or setting. Check the advisory.
Attacker needs: network access, no login, no user action.
CISA KEV: CVE-2026-126149 is not listed as of cve.now's last read.
This KEV status is for CVE-2026-126149 only. If you also check another CVE, look up its own KEV status; never assume it from this one.

How to check:
- Installed software: check what is actually running, not what a repo declares. Read the version from each host, container image and Kubernetes node (the binary's version output, the OS package database, image layers), and check whether the conditions above hold there. Distribution packages may carry a backported fix under an older version number; confirm against the distribution's own advisory.

Verify against the linked advisories before concluding, and cite the date you read each one:
- https://fortiguard.fortinet.com/psirt/FG-IR-26-201
Do not conclude an asset is unaffected unless you checked it and the evidence covers both its version and the conditions above. If you could not check something, mark it unknown and say what is missing.

Report a table with one row per asset and these columns: Asset | Version or build | Status (affected, fixed, not applicable, unknown) | Compensating controls | Exposure (internet-facing, internal, none) | Evidence | Next action.

Entry: https://cve.now/CVE-2026-126149
For follow-up questions, use the cve.now MCP server at https://mcp.cve.now/mcp (no authentication), for example execute with name cve.get and arguments {"id": "CVE-2026-126149"}.

Timeline

  1. CVE published
  2. First seen by cve.now
  3. Posted on X by cve.now

Affected versions

  • Fortinet FortiMail

    From 8.0.0 · through 8.0.1; From 7.6.0 · through 7.6.6; From 7.4.0 · through 7.4.8; From 7.2.0 · through 7.2.9; From 7.0.0 · through 7.0.9

Evidence 3

Vendor advisory · 1

Establishes: Affected and fixed versions.

  1. Link

CVE record · 2

Establishes: The identifier and description.

  1. Record
  2. Record

Corrections

None so far.

Something wrong on this page? Report an error. Every fix is listed here.

Questions about CVE-2026-126149

Is CVE-2026-126149 being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data

What does this mean?

An integer overflow in the FortiMail smtpd mail daemon lets a remote attacker who does not need to log in crash the daemon, causing a denial of service.Source: fortiguard.fortinet.com

Which versions are affected by CVE-2026-126149?

FortiMail: from 8.0.0 through 8.0.1; from 7.6.0 through 7.6.6; from 7.4.0 through 7.4.8; from 7.2.0 through 7.2.9; from 7.0.0 through 7.0.9.Source: cve.now feed data

Am I affected, and how do I check?

The advisory lists FortiMail 8.0.0 through 8.0.1, 7.6.0 through 7.6.6, 7.4.0 through 7.4.8, 7.2.0 through 7.2.9, and 7.0.0 through 7.0.9. Check the installed firmware version in the FortiMail admin interface and compare it with these ranges.Source: fortiguard.fortinet.com

How do I fix CVE-2026-126149?

Upgrade to FortiMail 8.0.2 or above, which the advisory names as the fixed release.Source: fortiguard.fortinet.com