The jline3 update to version 3.30.15 fixes two unauthenticated remote denial-of-service vulnerabilities in Telnet handling: CVE-2026-56740 allows remote memory exhaustion through unbounded NEW-ENVIRON variables, and CVE-2026-56741 allows remote DoS via unbounded NAWS Terminal Geometry. Additional fixes include protection against catastrophic regex backtracking by enforcing timeouts during regex matching, and security hardening measures like creating persisted history files with owner-only permissions and exclusive creation of native library temp files. These fixes address multiple related security advisories and improve overall robustness against denial-of-service attacks.

An unauthenticated remote attacker can exploit these vulnerabilities to cause denial-of-service conditions on affected systems by exhausting memory or triggering excessive processing via crafted Telnet input. This can disrupt service availability and potentially impact system stability. No information about code execution or data compromise is provided.

Update jline3 to version 3.30.15 or later, which includes fixes for the described vulnerabilities and additional security hardening. No other mitigation is indicated or required as the update addresses the issues directly.