# Riganti DotVVM ReDoS in routing engine

Source: https://junglewise.ai/threats/riganti-dotvvm-redos-in-routing-engine-dae343bd  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-06-19. Updated: 2026-06-19  
License: CC BY 4.0 with a link back

Severity: high · CVSS 8.2 · Published 2026-06-19

A vulnerability in the DotVVM web framework's routing system can allow an attacker to crash or slow down a web application. By sending a specially crafted web request to a site using specific URL patterns, an attacker can trigger a 'Regular Expression Denial of Service' (ReDoS), exhausting server resources and making the site unavailable to legitimate users. This affects applications that use multiple unconstrained parameters in their URL routes.

## Quick answers

**Is This vulnerability exploited in the wild?** No. Junglewise Threat Intelligence has no report of This vulnerability being exploited in the wild.

**How severe is This vulnerability?** High severity, with a CVSS score of 8.2, published 19 June 2026.

**Which products and versions are affected?** riganti DotVVM < 4.2.11, > 4.3.0-preview01-final, < 4.3.15, >= 5.0.0-preview01-final, < 5.0.0-preview09-final.

**Is there a fix for This vulnerability?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is This vulnerability attacked?** It is attacked over the network, in a software library.

**Am I affected?** Check whether anything you run is named in the advisory. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

A Regular Expression Denial of Service (ReDoS) vulnerability exists in the DotVVM routing engine (CWE-1333). The flaw is triggered when a route is defined with multiple unconstrained parameters in a single segment (e.g., "{a}-{b}-{c}") without being separated by a slash. An attacker can provide a long string of characters (such as 32,000 dashes) that causes the backtracking regex engine to consume excessive CPU cycles while attempting to match the route. Patches introduce a 1-second timeout for regex operations; upon timeout, the system attempts to switch to a non-backtracking engine or returns an HTTP 503 error. Fixes are available in versions 4.2.11, 4.3.15, and 5.0.0-preview09.

## Affected products

- riganti DotVVM < 4.2.11, > 4.3.0-preview01-final, < 4.3.15, >= 5.0.0-preview01-final, < 5.0.0-preview09-final

## Timeline

- 2026-06-18: disclosed
- 2026-06-19: advisory

## References

- [https://github.com/riganti/dotvvm/security/advisories/GHSA-c2g3-c4gc-w5wg](https://github.com/riganti/dotvvm/security/advisories/GHSA-c2g3-c4gc-w5wg)
- [https://www.dotvvm.com/docs/4.0/pages/concepts/routing/parameters](https://www.dotvvm.com/docs/4.0/pages/concepts/routing/parameters)
- [https://api.github.com/repos/riganti/dotvvm/security-advisories/GHSA-c2g3-c4gc-w5wg](https://api.github.com/repos/riganti/dotvvm/security-advisories/GHSA-c2g3-c4gc-w5wg)