# CVE-2026-72779: Craft CMS 5.0.0-RC1 before 5.10.6 Arbitrary File Read via SplFileObject

> Authenticated administrators can read arbitrary server files, including credentials, by exploiting a blocklist bypass in Twig template instantiation.

- **Severity:** High 8.7 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/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:** Yes
- **Published:** 11 Aug 2026
- **Updated:** 8 Oct 2026
- **Also known as:** GHSA-957r-qf9p-67xw

## What is CVE-2026-72779?

CVE-2026-72779 is a high-severity path traversal vulnerability in craftcms cms, published on 11 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Craft CMS 5.0.0-RC1 before 5.10.6 and 4.0.0-RC1 before 4.18.2 contain an arbitrary file read vulnerability. The create() Twig function restricts class instantiation using a 5-entry blocklist that does not include SplFileObject, allowing an authenticated administrator (with allowAdminChanges=true) to configure a malicious entry type title or URI format that instantiates SplFileObject in a non-sandboxed template context. When a user subsequently creates an entry in the affected section, arbitrary files on the server (such as .env containing the security key and database credentials) are read and rendered as entry titles.

Weakness: CWE-184 (Incomplete List of Disallowed Inputs)

## Which versions are affected by CVE-2026-72779?

4 open source packages ship an affected version, including craftcms/cms.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `craftcms/cms` | Packagist | From 4.0.0-RC1 | 4.18.2 |
| `craftcms/cms` | Packagist | From 4.0.0-RC1 | 4.18.2 |
| `craftcms/cms` | Packagist | From 5.0.0-RC1 | 5.10.6 |
| `craftcms/cms` | Packagist | From 5.0.0-RC1 | 5.10.6 |

## How do I fix CVE-2026-72779?

Upgrade craftcms/cms to a fixed version for your release line: 4.18.2 or 5.10.6.

## Is CVE-2026-72779 being exploited?

There is no known exploitation of CVE-2026-72779 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-72779 and fix it if it is affected.

What it is: CVE-2026-72779 is a high-severity path traversal vulnerability in craftcms cms, published on 11 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-2026-72779 in the wild and no public exploit code.

Affected packages and fixed versions:
- craftcms/cms (Packagist): affected from 4.0.0-RC1; fixed in 4.18.2
- craftcms/cms (Packagist): affected from 4.0.0-RC1; fixed in 4.18.2
- craftcms/cms (Packagist): affected from 5.0.0-RC1; fixed in 5.10.6
- craftcms/cms (Packagist): affected from 5.0.0-RC1; fixed in 5.10.6

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-2026-72779/ (Markdown: https://insights.sbomify.com/CVE-2026-72779/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-72779
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-72779
- OSV: https://osv.dev/vulnerability/CVE-2026-72779

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-72779/
Summaries are generated and may contain mistakes; the official description above is the record.