Bug 2529412 - CVE-2026-56740 jline: JLine3 Telnet Server: Denial of Service via excessive environment variable injection [fedora-all]
Summary: CVE-2026-56740 jline: JLine3 Telnet Server: Denial of Service via excessive e...
Keywords:
Status: NEW
Alias: None
Product: Fedora
Classification: Fedora
Component: jline
Version: rawhide
Hardware: Unspecified
OS: Unspecified
high
high
Target Milestone: ---
Assignee: Marián Konček
QA Contact: Fedora Extras Quality Assurance
URL:
Whiteboard: {"flaws": ["151e68b0-7ba5-4d59-a4c6-b...
Depends On:
Blocks: CVE-2026-56740
TreeView+ depends on / blocked
 
Reported: 2026-09-07 12:23 UTC by Ganesh
Modified: 2026-09-07 12:23 UTC (History)
3 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed:
Type: ---
Embargoed:


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Description Ganesh 2026-09-07 12:23:07 UTC
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.

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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