# CVE-2026-79988: Authenticated RCE through Twig sandbox escape

> Authenticated attackers can execute arbitrary code by exploiting a Twig sandbox escape in Craft CMS that permits dangerous Yii framework functionality.

- **Severity:** High 8.7 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 27 Aug 2026
- **Updated:** 28 Aug 2026
- **Also known as:** GHSA-9fvq-jx89-q558

## What is CVE-2026-79988?

CVE-2026-79988 is a high-severity code injection vulnerability in craftcms cms, published on 27 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

The Twig sandbox mechanism in Craft CMS is configured to allow dangerous functionality from the Yii framework, leading to authenticated RCE similar to previously disclosed vulnerabilities.

Weakness: CWE-693 (Protection Mechanism Failure)

## Which versions are affected by CVE-2026-79988?


## How do I fix CVE-2026-79988?

No fix has been published for CVE-2026-79988 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-79988 being exploited?

There is no known exploitation of CVE-2026-79988 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-79988 and fix it if it is affected.

What it is: CVE-2026-79988 is a high-severity code injection vulnerability in craftcms cms, published on 27 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-79988 in the wild and no public exploit code.

Affected product: craftcms cms. 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-2026-79988/ (Markdown: https://insights.sbomify.com/CVE-2026-79988/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-79988
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-79988
- OSV: https://osv.dev/vulnerability/CVE-2026-79988

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-79988/
Summaries are generated and may contain mistakes; the official description above is the record.