Shescape Inefficient Regular Expression Complexity vulnerability

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

• shescape project shescape1.5.1 and later · before 1.5.10

Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

• ericcornelissen shescape

  • >= 1.5.1, < 1.5.10affected

Other highest-scoring records for the same primary product.

• CVE-2022-31180Insufficient escaping of whitespace in shescape
  40Plan
• CVE-2022-31179Insufficient escaping of line feeds for CMD in shescape
  39Monitor
• CVE-2023-40185Shescape on Windows escaping may be bypassed in threaded context
  34Monitor
• CVE-2021-21384Null characters not escaped in shescape
  31Monitor
• CVE-2022-25918Regular Expression Denial of Service (ReDoS)
  30Monitor
• CVE-2026-32094Shescape escape() leaves bracket glob expansion active on Bash, BusyBox, and Dash
  27Monitor

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Root cause

Code that parses nested structures sets no depth or size limit. A small input can turn into a disproportionate processing load.

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

1function expand(node) {2  return node.children.map(expand);3}

1const MAX_DEPTH = 32;2function expand(node, depth = 0) {3  if (depth > MAX_DEPTH) throw new Error("too deep");4  return node.children.map((c) => expand(c, depth + 1));5}

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.