JLine up to 3.30.14/4.3.0 Less Viewer Less.java getPattern resource consumption

Summaryinfo

A vulnerability classified as problematic was found in JLine up to 3.30.14/4.3.0. The impacted element is the function getPattern of the file builtins/src/main/java/org/jline/builtins/Less.java of the component Less Viewer. Executing a manipulation can lead to resource consumption. This vulnerability appears as CVE-2026-77423. The attack may be performed from remote. There is no available exploit. Upgrading the affected component is advised.

Detailsinfo

A vulnerability has been found in JLine up to 3.30.14/4.3.0 and classified as problematic. This vulnerability affects the function getPattern of the file builtins/src/main/java/org/jline/builtins/Less.java of the component Less Viewer. The manipulation with an unknown input leads to a resource consumption vulnerability. The CWE definition for the vulnerability is CWE-400. The product does not properly control the allocation and maintenance of a limited resource, thereby enabling an actor to influence the amount of resources consumed, eventually leading to the exhaustion of available resources. As an impact it is known to affect availability. CVE summarizes:

JLine is a Java library for handling console input. From 3.0.0 until 3.30.15 and 4.3.1, the JLine built-in less viewer passes user-controlled search and display-filter patterns from getPattern(boolean doDisplayPattern) in builtins/src/main/java/org/jline/builtins/Less.java directly to Java's backtracking regular expression engine and repeatedly applies them to file content. A nested-quantifier expression evaluated against non-matching lines can consume excessive CPU and indefinitely block the session thread, and repeated sessions in Telnet or SSH deployments can exhaust a bounded worker pool. This issue is fixed in versions 3.30.15 and 4.3.1.

The advisory is shared for download at github.com. This vulnerability was named CVE-2026-77423 since 08/20/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. There are known technical details, but no exploit is available. The MITRE ATT&CK project declares the attack technique as T1499.

Upgrading to version 3.30.15 or 4.3.1 eliminates this vulnerability.

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Productinfo

Name

• JLine

Version

• 3.30.0
• 3.30.1
• 3.30.2
• 3.30.3
• 3.30.4
• 3.30.5
• 3.30.6
• 3.30.7
• 3.30.8
• 3.30.9
• 3.30.10
• 3.30.11
• 3.30.12
• 3.30.13
• 3.30.14
• 4.0
• 4.1
• 4.2
• 4.3.0

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