CVE-2026-56740
Description
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.
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
No mitigations published for this CVE yet.
The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.
✚ Propose a mitigation on Community → Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here withsource_tier=community-verified.
OS impact
SUSE Affected 1 release
| Version | Status | Fixed in |
|---|---|---|
| — | Affected | — |
References
- https://github.com/jline/jline3/commit/0389f0ee6d0375901b602671ad5dafd4d1d4ee09
- https://github.com/jline/jline3/commit/4ee3a73849ffb9a85ec748e4e8cd8f6d81f84f40
- https://github.com/jline/jline3/commit/934f09e6128cee33c2b13d42b6e859c1ee2d194b
- https://github.com/jline/jline3/pull/2000
- https://github.com/jline/jline3/pull/2001
- https://github.com/jline/jline3/releases/tag/4.0.16
- https://github.com/jline/jline3/releases/tag/4.2.1
- https://github.com/jline/jline3/releases/tag/jline-3.30.14
- https://github.com/jline/jline3/security/advisories/GHSA-47qp-hqvx-6r3f
- https://www.suse.com/security/cve/CVE-2026-56740.html
CWEs
CWE-400
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.