WaratekVRT Sign in

CVE-2026-56741 JLine

Affected softwareJLine
Severity7.5 High CVSS 3.1
Fixed in4.2.1, 4.0.16, 3.30.14
WeaknessUncontrolled resource consumption (CWE-400)
Published17 Jul 2026
Updated24 Oct 2026

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 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.

Exploitation status

Proof of concept only

A proof of concept exists, but no reviewed exploit catalogue lists this CVE.

  • CISA KEV not listed
  • VulnCheck KEV not listed
  • CISA Vulnrichment exploitation: poc CISA recorded that an exploit has been demonstrated. Automatable: yes, technical impact: partial.
  • Indexed PoC none indexed
  • EPSS 0.60% chance in 30 days

Waratek protection

No exploit published

Within Waratek scope. In the sources we check, nobody has published exploit code for this CVE or reported it being exploited.

A public code fix exists: jline/jline3 3ea9cad.

  • Protection none
  • Action unverified
  • Review automated Upstream data
  • Record active
Decided by Exploit code for this candidate, published in a reviewed catalogue or a GitHub repository with 5 or more stars, or in use per CISA or VulnCheck; not only a CISA verdict, a forecast, or nothing at all
Finding This CVE is not listed in CISA KEV or VulnCheck KEV, CISA Vulnrichment records no active exploitation, no reviewed exploit catalogue carries an entry for it, and no GitHub PoC repository for it has 5 or more stars. Nobody has published exploit code worth tracing, so it is not a candidate for a rule ahead of the ones where somebody has; an upstream fix path does exist, so the remediation half of the candidacy still holds. This is a statement about what has been published, not about whether the defect is reachable or serious.
Candidate fix https://github.com/jline/jline3/commit/3ea9cad8699714dc072fade29d36be0d1e23d708 : a commit: the change itself

Affected software and releases

Oracle advisories

AdvisoryTypeQuarterProducts Oracle names in its risk matrix
Oracle Critical Patch Update October 2026 ↗ CPU 2026-Q4 Oracle Fusion Middleware / Centralized Thirdparty Jars (jline) (12.2.1.4.0, 14.1.1.0.0)

Oracle components and versions

FamilyComponentVersions, as Oracle lists themRead as
Oracle Fusion Middleware Centralized Thirdparty Jars (jline) 12.2.1.4.0, 14.1.1.0.0 12.2.1.4.0 · 14.1.1.0.0

Maven packages

Affected and fixed versions, from OSV.dev
PackageIntroducedFixedLast affected
org.jline:jline-remote-telnet 4.1.0 4.2.1 unbounded
org.jline:jline-remote-telnet 4.0.0 4.0.16 unbounded
org.jline:jline-remote-telnet 0 3.30.14 unbounded

Products and versions

2 products, 6 version entries
SourceVendorProductSchemeAffected versions
nvd jline jline generic < 3.30.14 · ≥ 4.0.0 and < 4.0.16 · ≥ 4.1.0 and < 4.2.1
osv org.jline jline-remote-telnet generic < 3.30.14 · ≥ 4.0.0 and < 4.0.16 · ≥ 4.1.0 and < 4.2.1

References

URLTags
https://github.com/jline/jline3/commit/3ea9cad8699714dc072fade29d36be0d1e23d708 commit
https://github.com/jline/jline3/security/advisories/GHSA-2r2c-cx56-8933 WEB
https://github.com/jline/jline3/pull/2000 WEB
https://github.com/jline/jline3/commit/733eb353dca7b0ea0252e724445b6defa29c393e WEB
https://github.com/jline/jline3/commit/86b7ba7801988aadb1a67555629522a71d603bd3 WEB
https://github.com/jline/jline3 PACKAGE
https://github.com/jline/jline3/releases/tag/4.0.16 WEB
https://github.com/jline/jline3/releases/tag/4.2.1 WEB

Timeline

Published2026-07-17By the CVE Program.
NVD record modified2026-10-24NVD's own last-modified date for this record.