# CVE-2026-77136: Server-Side Template Injection in extension "powermail" (powermail)

> Unauthenticated attackers can inject Fluid template syntax into sender name fields to execute code and read sensitive data in TYPO3 powermail.

- **Severity:** Critical 9.5 (`CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 25 Aug 2026
- **Updated:** 25 Aug 2026
- **Also known as:** GHSA-6956-f2gq-2c74

## What is CVE-2026-77136?

CVE-2026-77136 is a critical code injection vulnerability in TYPO3 Extension "powermail", published on 25 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

The extension passes the raw value of a form field configured as "This field contains the name of the sender" directly into a Fluid View as template source, without any sanitization, and renders it. An anonymous, unauthenticated user can submit Fluid template syntax in that field to execute arbitrary Fluid ViewHelpers leading to disclosure of server configuration, environment variables and application source, and potentially remote code execution. Exploitation requires only that a form field is configured as the sender_name field, a common and default-adjacent Powermail configuration. No authentication or user interaction beyond a normal form submission is required. This vulnerability is reported to be actively exploited in the wild.

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

## Which versions are affected by CVE-2026-77136?


## How do I fix CVE-2026-77136?

No fix has been published for CVE-2026-77136 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-77136 being exploited?

There is no known exploitation of CVE-2026-77136 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-77136 and fix it if it is affected.

What it is: CVE-2026-77136 is a critical code injection vulnerability in TYPO3 Extension "powermail", published on 25 Aug 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-2026-77136 in the wild and no public exploit code.

Affected product: TYPO3 Extension "powermail". 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-2026-77136/ (Markdown: https://insights.sbomify.com/CVE-2026-77136/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-77136
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-77136
- OSV: https://osv.dev/vulnerability/CVE-2026-77136

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-77136/
Summaries are generated and may contain mistakes; the official description above is the record.