{"id":"CVE-2026-56740","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-56740","generatedAt":"2026-10-28T03:29:27.573Z","title":"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…","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.","published":"2026-07-17T22:17:57.000Z","lastModified":"2026-10-24T20:10:00.000Z","status":"Analyzed","sourceIdentifier":"security-advisories@github.com","cvss":{"version":"3.1","score":7.5,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},"cwe":["CWE-400"],"affected":["jline/jline"],"epss":{"score":0.00884,"percentile":0.58959,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"High impact if exploited, but EPSS currently rates exploitation as unlikely (0.88%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[],"references":[{"url":"https://github.com/jline/jline3/commit/0389f0ee6d0375901b602671ad5dafd4d1d4ee09","tags":["Patch"],"source":"security-advisories@github.com"},{"url":"https://github.com/jline/jline3/commit/4ee3a73849ffb9a85ec748e4e8cd8f6d81f84f40","tags":["Patch"],"source":"security-advisories@github.com"},{"url":"https://github.com/jline/jline3/commit/934f09e6128cee33c2b13d42b6e859c1ee2d194b","tags":["Patch"],"source":"security-advisories@github.com"},{"url":"https://github.com/jline/jline3/pull/2000","tags":["Issue Tracking"],"source":"security-advisories@github.com"},{"url":"https://github.com/jline/jline3/pull/2001","tags":["Issue Tracking"],"source":"security-advisories@github.com"},{"url":"https://github.com/jline/jline3/releases/tag/4.0.16","tags":["Release Notes"],"source":"security-advisories@github.com"},{"url":"https://github.com/jline/jline3/releases/tag/4.2.1","tags":["Release Notes"],"source":"security-advisories@github.com"},{"url":"https://github.com/jline/jline3/releases/tag/jline-3.30.14","tags":["Release Notes"],"source":"security-advisories@github.com"},{"url":"https://github.com/jline/jline3/security/advisories/GHSA-47qp-hqvx-6r3f","tags":["Exploit","Vendor Advisory"],"source":"security-advisories@github.com"},{"url":"https://github.com/jline/jline3/security/advisories/GHSA-47qp-hqvx-6r3f","tags":["Exploit","Vendor Advisory"],"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-56740","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}