CVSS 3.1
7.5 highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HCVE-2026-4926
High (7.5) in pillarjs path-to-regexp. EPSS 0.8% chance of exploitation in the next 30 days. Fixed in path-to-regexp 8.4.0.
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.
Severity
- EPSS
- 0.8% chance of exploitation in the next 30 days; higher than 56% of CVEs (scores of 2026-10-31)
- CWEs
- CWE-400, CWE-1333
- Published
- Modified
- Record from
- the NVD, synced
Affected
- pillarjs:path-to-regexp
Packages (OSV)
| Advisory | Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|---|
| GHSA-j3q9-mxjg-w52f | npm | path-to-regexp | >=8.0.0 <8.4.0 | 8.4.0 |