CVE-2026-56741 (GCVE-0-2026-56741)

Vulnerability from cvelistv5 – Published: 2026-07-17 21:15 – Updated: 2026-07-20 15:21
VLAI
Title
JLine: Unauthenticated Remote DoS via Unbounded Telnet NAWS Terminal Geometry
Summary
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 apply an upper bound to terminal dimensions received via the Telnet NAWS option, and TelnetIO.handleNAWS() in TelnetIO.java:856-879 reads client-supplied width and height as 16-bit unsigned integers and passes values such as 65535x65535 to setTerminalGeometry(), allowing an unauthenticated remote attacker to repeatedly alternate values and trigger continuous expensive rendering work that causes CPU exhaustion and denial of service. This issue is fixed in versions 3.30.14, 4.0.16, and 4.2.1.
Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
SSVC
Exploitation: poc Automatable: yes Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-07-20 15:21 UTC
CWE
  • CWE-400 - Uncontrolled Resource Consumption
Assigner
References
Impacted products
Vendor Product Version CPE status
jline jline3 Affected: < 3.30.14
Affected: >= 4.0.0, < 4.0.16
Affected: >= 4.1.0, < 4.2.1
guessed Create a notification for this product.
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