CVE-2026-55676: cisagov Malcolm · Unrestricted File Upload
Affects cisagov MalcolmSource CVE Database V5
Not known to be exploited · CVSS 8.8 High : upgrade to 26.06.1 soon.
Data as of 8 Nov 2026, 23:24 UTC
- EPSS
- 0.6% chance of exploitation in 30 days – higher than 49% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 26.06.1
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 11 Aug 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 9 Nov 2026.
What to do
Upgrade Malcolm and cisagov/Malcolm to 26.06.1.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| cisagovMalcolm | Affected
| Fixed in
|
GitHubcisagov/Malcolmpkg:github/cisagov/MalcolmOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
Version 26.06.1 of Malcolm fixes this vulnerability by restricting file uploads and execution. Users should upgrade to version 26.06.1 or later to remediate this issue. Until upgrading, restrict the ROLE_UPLOAD permission carefully and avoid granting it to untrusted users.
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.
References
- github.com/cisagov/Malcolm/security/advisories/GHSA-8cvp-m7pg-qrp7 (opens in a new tab)
- github.com/cisagov/Malcolm/releases/tag/v26.06.1 (opens in a new tab)
- cisa.gov/news-events/ics-advisories/icsa-26-230-01 (opens in a new tab)
- github.com/cisagov/CSAF/blob/develop/csaf_files/OT/white/2026/icsa-26-230-01.json (opens in a new tab)