JLine: Unauthenticated Remote Memory Exhaustion via Unbounded Telnet NEW-ENVIRON Variables

Affected versions

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

• jline jlinebefore 3.30.14
• jline jline4.0.0 and later · before 4.0.16
• jline jline4.1.0 and later · before 4.2.1

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.

• jline jline3

  • < 3.30.14, >= 4.0.0, < 4.0.16, >= 4.1.0, < 4.2.1affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

Other highest-scoring records for the same primary product.

• CVE-2026-56741JLine: Unauthenticated Remote DoS via Unbounded Telnet NAWS Terminal Geometry
  30Monitor
• CVE-2023-50572An issue in the component GroovyEngine.execute of jline-groovy v3.24.1 allows attackers to cause an OOM (OutofMemory) error.
  22Monitor

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.