CVE-2026-4926EPSS p53.1%

CVE-2026-4926CVE-2026-4926

pillarjs / path-to-regexp

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.

Scoring

CVSS 7.5 ()
VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS0.79% probability of exploitation · percentile 53.1% · 2026-08-13T12:03:51Z
Last modified2026-08-05
Sourced from NVD + FIRST.org EPSS. Curated for EU compliance use cases by Adam Lundqvist, Founder at SQUR.