# CVE-2026-44129: Server-side template injection

> Remote attackers can execute arbitrary template expressions in SEPPmail Secure Email Gateway, potentially achieving remote code execution.

- **Severity:** High 8.3 (`CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:L/VA:L/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-wc7f-vvj8-28m9

## What is CVE-2026-44129?

CVE-2026-44129 is a high-severity code injection 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 contains a server-side template injection vulnerability in the new GINA UI because an endpoint accepts attacker-controlled template, allowing remote attackers to execute arbitrary template expressions and potentially achieve remote code execution depending on the enabled template plugins.

Weakness: CWE-1336 (Improper Neutralization of Special Elements Used in a Template Engine)

## Which versions are affected by CVE-2026-44129?


## How do I fix CVE-2026-44129?

No fix has been published for CVE-2026-44129 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-44129 being exploited?

There is no known exploitation of CVE-2026-44129 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-44129 and fix it if it is affected.

What it is: CVE-2026-44129 is a high-severity code injection 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-2026-44129 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-2026-44129/ (Markdown: https://insights.sbomify.com/CVE-2026-44129/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-44129
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-44129
- OSV: https://osv.dev/vulnerability/CVE-2026-44129

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-44129/
Summaries are generated and may contain mistakes; the official description above is the record.