Malcolm vulnerable to RCE via unrestricted .php upload to the file-upload component (CVE-2026-55676) | HOL Guard CVE

High · CVSS 8.8CVE-2026-55676

Malcolm vulnerable to RCE via unrestricted .php upload to the file-upload component

Answer in brief

CVE-2026-55676 records a High severity (CVSS 8.8) vulnerability in Malcolm vulnerable to RCE via unrestricted .php upload to the file-upload component. The current sources do not mark it as known exploited. The current feed maps cisagov/Malcolm (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Aug 11, 2026Updated Sep 9, 2026Source checked Sep 25, 2026First seen by HOL Aug 11, 2026Material review Sep 9, 2026

Upstream Advisory

Key facts

Risk: High · CVSS 8.8
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Available

Why this deserves its current priority

CVSS is 8.8. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps cisagov/Malcolm (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
cisagov/Malcolmgeneric	<26.06.1	26.06.1

Recommended response

Check inventory. Check lockfiles and deployed manifests for cisagov/Malcolm.
Review the reported fix. Update cisagov/Malcolm to 26.06.1 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Aug 11, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 9, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Aug 11, 2026

Sources and claim methodology

Upstream source 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.

Quoted source text, attributed separately from HOL analysis.