EUVD-2026-16324
GHSA-j3q9-mxjg-w52f
CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Lifecycle Timeline
4Tags
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.
Analysis
The path-to-regexp library versions 8.0.0 through 8.3.0 suffer from catastrophic regular expression denial of service via exponential regex generation when route patterns contain multiple sequential optional groups in curly-brace syntax. Remote unauthenticated attackers can trigger resource exhaustion by submitting crafted route patterns, causing application-level denial of service with CVSS 7.5 (High severity). …
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Remediation
Within 24 hours: Identify all applications and dependencies using path-to-regexp versions 8.0.0 through 8.3.0 in your environment. Within 7 days: Upgrade affected instances to version 8.4.0 or later. …
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Priority Score
Vendor Status
Debian
| Release | Status | Fixed Version | Urgency |
|---|---|---|---|
| bullseye | vulnerable | 6.2.0-1 | - |
| bookworm | vulnerable | 6.2.1-1 | - |
| trixie | vulnerable | 6.3.0-1 | - |
| forky, sid | vulnerable | 8.3.0-1 | - |
| (unstable) | fixed | (unfixed) | - |
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External POC / Exploit Code
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