# CVE-2026-27891: Remote Code Execution (RCE) via Zip Slip in Plugin Upload Mechanism

> Attackers can achieve remote code execution by uploading a malicious ZIP file that exploits path traversal to overwrite PHP files.

- **Severity:** High 7.2 (`CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 18 May 2026
- **Updated:** 19 May 2026
- **Also known as:** GHSA-3pgc-xqg9-cfr6

## What is CVE-2026-27891?

CVE-2026-27891 is a high-severity path traversal vulnerability in NeoRazorX facturascripts, published on 18 May 2026. An attacker needs administrator access to exploit it, with no action from the victim.

### Official description

FacturaScripts is an open source accounting and invoicing software. Versions 2026 and below contain a critical vulnerability in the Plugins::add() function. The system fails to properly validate the file paths within uploaded ZIP archives. This allows an attacker to perform a Zip Slip attack, leading to Arbitrary File Write and Remote Code Execution (RCE) by overwriting sensitive .php files outside the designated plugins directory. The vulnerability is located in Plugins.php. While the testZipFile function attempts to validate that the ZIP contains only one root folder, it does not sanitize or validate the individual file paths within that folder. An attacker can bypass this check by naming a file ValidPluginName/../../shell.php. The explode function will see ValidPluginName as the root folder, satisfying the count($folders) != 1 check. However, during extraction, the ../../ sequence triggers a path traversal, allowing the file to be written anywhere the web server has permissions the root directory. This issue is fixed in version 2026.1.

Weakness: CWE-434 (Unrestricted Upload of File with Dangerous Type), CWE-20 (Improper Input Validation)

## Which versions are affected by CVE-2026-27891?

2 open source packages ship an affected version, including facturascripts/facturascripts.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `facturascripts/facturascripts` | Packagist | All versions to 2025.71 | None |
| `facturascripts/facturascripts` | Packagist | All versions to 2025.71 | None |

## How do I fix CVE-2026-27891?

No fix has been published for CVE-2026-27891 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-27891 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-27891 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-27891 and fix it if it is affected.

What it is: CVE-2026-27891 is a high-severity path traversal vulnerability in NeoRazorX facturascripts, published on 18 May 2026. An attacker needs administrator access to exploit it, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-27891 exists.

Affected packages and fixed versions:
- facturascripts/facturascripts (Packagist): affected all versions up to 2025.71; no fix listed
- facturascripts/facturascripts (Packagist): affected all versions up to 2025.71; no fix listed

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-2026-27891/ (Markdown: https://insights.sbomify.com/CVE-2026-27891/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-27891
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-27891
- OSV: https://osv.dev/vulnerability/CVE-2026-27891

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-27891/
Summaries are generated and may contain mistakes; the official description above is the record.