# CVE-2026-126149: Integer overflow in FortiMail

> Remote unauthenticated attackers can crash the FortiMail daemon via an integer overflow.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:R`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Harmful if only installed:** No
- **Needs a specific call:** No
- **Fix available:** No
- **Published:** 11 Nov 2026
- **Updated:** 11 Nov 2026
- **Also known as:** GHSA-cmjf-9f9h-8fvg

## What is CVE-2026-126149?

CVE-2026-126149 is a high-severity integer overflow vulnerability in Fortinet FortiMail, published on 11 Nov 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official 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.

Weakness: CWE-190 (Integer Overflow or Wraparound)

## Which versions are affected by CVE-2026-126149?

An affected version is exposed as installed. No special setting or call is needed.


## How do I fix CVE-2026-126149?

No fix has been published for CVE-2026-126149 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-126149 being exploited?

There is no known exploitation of CVE-2026-126149 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-126149 and fix it if it is affected.

What it is: CVE-2026-126149 is a high-severity integer overflow vulnerability in Fortinet FortiMail, published on 11 Nov 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-126149 in the wild and no public exploit code.
Exposure: An affected version is exposed as installed. No special setting or call is needed.

Affected product: Fortinet FortiMail. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-126149/ (Markdown: https://insights.sbomify.com/CVE-2026-126149/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-126149
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-126149
- OSV: https://osv.dev/vulnerability/CVE-2026-126149

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-126149/
Summaries are generated and may contain mistakes; the official description above is the record.