FKIE_CVE-2026-56741

Vulnerability from fkie_nvd - Published: 2026-07-17 22:17 - Updated: 2026-07-17 22:17
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 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.
References
security-advisories@github.comhttps://github.com/jline/jline3/commit/3ea9cad8699714dc072fade29d36be0d1e23d708
security-advisories@github.comhttps://github.com/jline/jline3/commit/733eb353dca7b0ea0252e724445b6defa29c393e
security-advisories@github.comhttps://github.com/jline/jline3/commit/86b7ba7801988aadb1a67555629522a71d603bd3
security-advisories@github.comhttps://github.com/jline/jline3/pull/2000
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/security/advisories/GHSA-2r2c-cx56-8933
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 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."
    }
  ],
  "id": "CVE-2026-56741",
  "lastModified": "2026-07-17T22:17:57.317",
  "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"
      }
    ]
  },
  "published": "2026-07-17T22:17:57.317",
  "references": [
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/jline/jline3/commit/3ea9cad8699714dc072fade29d36be0d1e23d708"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/jline/jline3/commit/733eb353dca7b0ea0252e724445b6defa29c393e"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/jline/jline3/commit/86b7ba7801988aadb1a67555629522a71d603bd3"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/jline/jline3/pull/2000"
    },
    {
      "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/security/advisories/GHSA-2r2c-cx56-8933"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Received",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-400"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Primary"
    }
  ]
}



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