FKIE_CVE-2026-56740

Vulnerability from fkie_nvd - Published: 2026-07-17 22:17 - Updated: 2026-07-20 15:16
Severity
7.5 (High) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Summary
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.
References
security-advisories@github.comhttps://github.com/jline/jline3/commit/0389f0ee6d0375901b602671ad5dafd4d1d4ee09
security-advisories@github.comhttps://github.com/jline/jline3/commit/4ee3a73849ffb9a85ec748e4e8cd8f6d81f84f40
security-advisories@github.comhttps://github.com/jline/jline3/commit/934f09e6128cee33c2b13d42b6e859c1ee2d194b
security-advisories@github.comhttps://github.com/jline/jline3/pull/2000
security-advisories@github.comhttps://github.com/jline/jline3/pull/2001
security-advisories@github.comhttps://github.com/jline/jline3/releases/tag/4.0.16
security-advisories@github.comhttps://github.com/jline/jline3/releases/tag/4.2.1
security-advisories@github.comhttps://github.com/jline/jline3/releases/tag/jline-3.30.14
security-advisories@github.comhttps://github.com/jline/jline3/security/advisories/GHSA-47qp-hqvx-6r3f
134c704f-9b21-4f2e-91b3-4a467353bcc0https://github.com/jline/jline3/security/advisories/GHSA-47qp-hqvx-6r3f
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "jline3",
          "vendor": "jline",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 3.30.14"
            },
            {
              "status": "affected",
              "version": "\u003e= 4.0.0, \u003c 4.0.16"
            },
            {
              "status": "affected",
              "version": "\u003e= 4.1.0, \u003c 4.2.1"
            }
          ]
        }
      ],
      "source": "security-advisories@github.com"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "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."
    }
  ],
  "id": "CVE-2026-56740",
  "lastModified": "2026-07-20T15:16:44.080",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 7.5,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 3.6,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-56740",
          "options": [
            {
              "exploitation": "poc"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-07-20T13:57:48.412665Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-07-17T22:17:57.153",
  "references": [
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/jline/jline3/commit/0389f0ee6d0375901b602671ad5dafd4d1d4ee09"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/jline/jline3/commit/4ee3a73849ffb9a85ec748e4e8cd8f6d81f84f40"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/jline/jline3/commit/934f09e6128cee33c2b13d42b6e859c1ee2d194b"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/jline/jline3/pull/2000"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/jline/jline3/pull/2001"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/jline/jline3/releases/tag/4.0.16"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/jline/jline3/releases/tag/4.2.1"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/jline/jline3/releases/tag/jline-3.30.14"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/jline/jline3/security/advisories/GHSA-47qp-hqvx-6r3f"
    },
    {
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "url": "https://github.com/jline/jline3/security/advisories/GHSA-47qp-hqvx-6r3f"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Received",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-400"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Secondary"
    }
  ]
}



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  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
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