Inefficient Regular Expression Complexity Affecting pcs-snmp package, versions *


Severity

Recommended
0.0
medium
0
10

Based on CentOS security rating.

Threat Intelligence

EPSS
0.05% (16th percentile)

Do your applications use this vulnerable package?

In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.

Test your applications

Snyk Learn

Learn about Inefficient Regular Expression Complexity vulnerabilities in an interactive lesson.

Start learning
  • Snyk IDSNYK-CENTOS9-PCSSNMP-15857013
  • published31 Mar 2026
  • disclosed26 Mar 2026

Introduced: 26 Mar 2026

NewCVE-2026-4867  (opens in a new tab)
CWE-1333  (opens in a new tab)

How to fix?

There is no fixed version for Centos:9 pcs-snmp.

NVD Description

Note: Versions mentioned in the description apply only to the upstream pcs-snmp package and not the pcs-snmp package as distributed by Centos. See How to fix? for Centos:9 relevant fixed versions and status.

Impact:

A bad regular expression is generated any time you have three or more parameters within a single segment, separated by something that is not a period (.). For example, /:a-:b-:c or /:a-:b-:c-:d. The backtrack protection added in path-to-regexp@0.1.12 only prevents ambiguity for two parameters. With three or more, the generated lookahead does not block single separator characters, so capture groups overlap and cause catastrophic backtracking.

Patches:

Upgrade to path-to-regexp@0.1.13

Custom regex patterns in route definitions (e.g., /:a-:b([^-/]+)-:c([^-/]+)) are not affected because they override the default capture group.

Workarounds:

All versions can be patched by providing a custom regular expression for parameters after the first in a single segment. As long as the custom regular expression does not match the text before the parameter, you will be safe. For example, change /:a-:b-:c to /:a-:b([^-/]+)-:c([^-/]+).

If paths cannot be rewritten and versions cannot be upgraded, another alternative is to limit the URL length.

CVSS Base Scores

version 3.1