CVE-2026-56740

JLine is a Java library for handling console input. Prior to 3.30.14, 4.0.16, and 4.2.1, the JLine3 Telnet server remote-telnet module does not limit the number of environment variables a client may inject via the Telnet NEW-ENVIRON option, and TelnetIO.readNEVariables() in TelnetIO.java:1127-1180 stores each variable pair in a HashMap held by ConnectionData, allowing an unauthenticated attacker to flood unique variable pairs before the terminating IAC SE byte and exhaust JVM heap memory with an OutOfMemoryError. This issue is fixed in versions 3.30.14, 4.0.16, and 4.2.1.

CVSS v3 7.5 HIGH

7.5^/10

CVSS v3 : HIGH

Vector :

Exploitability : 3.9 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://github.com/jline/jline3/commit/0389f0ee6d0375901b602671ad5dafd4d1d4ee09	Patch
https://github.com/jline/jline3/commit/4ee3a73849ffb9a85ec748e4e8cd8f6d81f84f40	Patch
https://github.com/jline/jline3/commit/934f09e6128cee33c2b13d42b6e859c1ee2d194b	Patch
https://github.com/jline/jline3/pull/2000	Issue Tracking
https://github.com/jline/jline3/pull/2001	Issue Tracking
https://github.com/jline/jline3/releases/tag/4.0.16	Release Notes
https://github.com/jline/jline3/releases/tag/4.2.1	Release Notes
https://github.com/jline/jline3/releases/tag/jline-3.30.14	Release Notes
https://github.com/jline/jline3/security/advisories/GHSA-47qp-hqvx-6r3f	Exploit Vendor Advisory
https://github.com/jline/jline3/security/advisories/GHSA-47qp-hqvx-6r3f	Exploit Vendor Advisory

Configurations

Configuration 1 (hide)

OR	cpe:2.3:a:jline:jline::::::::
	cpe:2.3:a:jline:jline::::::::
	cpe:2.3:a:jline:jline::::::::

History

No history.

Information

Published : 2026-07-17 22:17

Updated : 2026-08-18 15:23

NVD link : CVE-2026-56740

Mitre link : CVE-2026-56740

CVE.ORG link : CVE-2026-56740

JSON object : View

Products Affected

jline

jline

CWE

CWE-400

Uncontrolled Resource Consumption

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