# CVE-2026-44126: Insecure deserialization

> Unauthenticated remote attackers can execute arbitrary code via insecure deserialization in the GINA UI of SEPPmail Secure Email Gateway.

- **Severity:** Critical 9.2 (`CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 8 May 2026
- **Updated:** 18 May 2026
- **Also known as:** GHSA-69wg-m4qc-c3qc

## What is CVE-2026-44126?

CVE-2026-44126 is a critical unsafe deserialization vulnerability in SEPPmail AG Secure Email Gateway, published on 8 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

SEPPmail Secure Email Gateway before version 15.0.4 insecurely deserializes untrusted data, which can be reached from the new GINA UI and may allow unauthenticated remote attackers to execute code via a crafted serialized object.

Weakness: CWE-502 (Deserialization of Untrusted Data)

## Which versions are affected by CVE-2026-44126?


## How do I fix CVE-2026-44126?

No fix has been published for CVE-2026-44126 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-44126 being exploited?

There is no known exploitation of CVE-2026-44126 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-44126 and fix it if it is affected.

What it is: CVE-2026-44126 is a critical unsafe deserialization vulnerability in SEPPmail AG Secure Email Gateway, published on 8 May 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-2026-44126 in the wild and no public exploit code.

Affected product: SEPPmail AG Secure Email Gateway. 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-2026-44126/ (Markdown: https://insights.sbomify.com/CVE-2026-44126/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-44126
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-44126
- OSV: https://osv.dev/vulnerability/CVE-2026-44126

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-44126/
Summaries are generated and may contain mistakes; the official description above is the record.