Bug 2501965 (CVE-2026-56740) - CVE-2026-56740 org.jline/jline-remote-telnet: JLine3 Telnet Server: Denial of Service via excessive environment variable injection
Summary: CVE-2026-56740 org.jline/jline-remote-telnet: JLine3 Telnet Server: Denial of...
Keywords:
Status: NEW
Alias: CVE-2026-56740
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
high
high
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On: 2529412
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-07-17 22:02 UTC by OSIDB Bzimport
Modified: 2026-09-07 12:23 UTC (History)
9 users (show)

Fixed In Version:
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Description OSIDB Bzimport 2026-07-17 22:02:18 UTC 
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.
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