# CVE-2026-4926: node-path-to-regexp: Impact:  A bad regular expression is generated any time you have multiple sequential optional groups (curly brace syn...

CVE-2026-4926 is fixed in node-path-to-regexp on 1 platform by DEBIAN-CVE-2026-4926 (version 8.4.0-1), released March 26, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-4926
- Priority: High
- CVSS: 7.5 (high)
- EPSS: 0.0081
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Mar 26, 2026

## Description

Impact:  A bad regular expression is generated any time you have multiple sequential optional groups (curly brace syntax), such as `{a}{b}{c}:z`. The generated regex grows exponentially with the number of groups, causing denial of service.  Patches:  Fixed in version 8.4.0.  Workarounds:  Limit the number of sequential optional groups in route patterns. Avoid passing user-controlled input as route patterns.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | node-path-to-regexp Debian 14 | 8.4.0-1 | [DEBIAN-CVE-2026-4926](https://patchblox.com/security/data/fix/linux/debian-cve-2026-4926.md) | Mar 26, 2026 |

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Data as of 2026-11-08T06:59:42Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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