Vulnerability Description
JLine is a Java library for handling console input. From 3.0.0 until 3.30.15 and 4.3.1, the JLine built-in nano editor's regex search mode passes a user-controlled search term from doSearch(String text) in builtins/src/main/java/org/jline/builtins/Nano.java to Java's backtracking regular expression engine without a timeout or backtracking bound. A nested-quantifier expression evaluated against non-matching buffer content can consume excessive CPU and indefinitely block the editor session thread, and remote multi-user deployments can lose a worker thread for each affected session. This issue is fixed in versions 3.30.15 and 4.3.1.
CVSS Score
MEDIUM
Related Weaknesses (CWE)
References
- https://github.com/jline/jline3/commit/1d5fc3099e77938b971e197211cad2d4fbb17541
- https://github.com/jline/jline3/commit/341ee69ccc57b7733c1b40d6993219b64b3206ae
- https://github.com/jline/jline3/pull/2012
- https://github.com/jline/jline3/pull/2018
- https://github.com/jline/jline3/releases/tag/4.3.1
- https://github.com/jline/jline3/releases/tag/jline-3.30.15
- https://github.com/jline/jline3/security/advisories/GHSA-ph9c-7hw9-vhhw
FAQ
What is CVE-2026-77421?
CVE-2026-77421 is a vulnerability with a CVSS score of 6.5 (MEDIUM). JLine is a Java library for handling console input. From 3.0.0 until 3.30.15 and 4.3.1, the JLine built-in nano editor's regex search mode passes a user-controlled search term from doSearch(String tex...
How severe is CVE-2026-77421?
CVE-2026-77421 has been rated MEDIUM with a CVSS base score of 6.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-77421?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.