FKIE_CVE-2026-50020

Vulnerability from fkie_nvd - Published: 2026-06-12 16:16 - Updated: 2026-06-17 10:57
Severity
5.3 (Medium) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Summary
Netty is a network application framework for development of protocol servers and clients. Prior to versions 4.1.135.Final and 4.2.15.Final, before reading the first request-line, `HttpObjectDecoder` skips every byte for which `Character.isISOControl(b)` is `true` (0x00–0x1F and 0x7F) as well as all whitespace. RFC 9112 §2.2 only asks servers to ignore empty CRLF lines preceding the request-line — a carefully scoped robustness allowance intended to handle HTTP/1.0 POST workarounds. Silently absorbing NUL bytes, SOH, STX, and other non-CRLF control characters goes significantly beyond this, and can be exploited for request-boundary confusion in pipelined or multiplexed transports where a front-end component treats those bytes differently. Versions 4.1.135.Final and 4.2.15.Final patch the issue.
References
security-advisories@github.comhttps://github.com/netty/netty/releases/tag/netty-4.1.135.FinalRelease Notes
security-advisories@github.comhttps://github.com/netty/netty/releases/tag/netty-4.2.15.FinalRelease Notes
security-advisories@github.comhttps://github.com/netty/netty/security/advisories/GHSA-hvcg-qmg6-jm4cVendor Advisory
134c704f-9b21-4f2e-91b3-4a467353bcc0https://github.com/netty/netty/security/advisories/GHSA-hvcg-qmg6-jm4cVendor Advisory
Impacted products
Vendor Product Version
netty netty *
netty netty *
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "netty",
          "vendor": "netty",
          "versions": [
            {
              "status": "affected",
              "version": "\u003e= 4.2.0.Final, \u003c 4.2.15.Final"
            },
            {
              "status": "affected",
              "version": "\u003c 4.1.135.Final"
            }
          ]
        }
      ],
      "source": "security-advisories@github.com"
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:netty:netty:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "3097D962-A32D-4467-AAE7-F4CBA3A349D2",
              "versionEndExcluding": "4.1.135",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:a:netty:netty:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "413D4611-A46C-4BE4-AB2F-D86282F65984",
              "versionEndExcluding": "4.2.15",
              "versionStartIncluding": "4.2.0",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Netty is a network application framework for development of protocol servers and clients. Prior to versions 4.1.135.Final and 4.2.15.Final, before reading the first request-line, `HttpObjectDecoder` skips every byte for which `Character.isISOControl(b)` is `true` (0x00\u20130x1F and 0x7F) as well as all whitespace. RFC 9112 \u00a72.2 only asks servers to ignore empty CRLF lines preceding the request-line \u2014 a carefully scoped robustness allowance intended to handle HTTP/1.0 POST workarounds. Silently absorbing NUL bytes, SOH, STX, and other non-CRLF control characters goes significantly beyond this, and can be exploited for request-boundary confusion in pipelined or multiplexed transports where a front-end component treats those bytes differently. Versions 4.1.135.Final and 4.2.15.Final patch the issue."
    }
  ],
  "id": "CVE-2026-50020",
  "lastModified": "2026-06-17T10:57:35.237",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 5.3,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "NONE",
          "integrityImpact": "LOW",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 1.4,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-50020",
          "options": [
            {
              "exploitation": "poc"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-06-12T15:56:10.783796Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-06-12T16:16:31.447",
  "references": [
    {
      "source": "security-advisories@github.com",
      "tags": [
        "Release Notes"
      ],
      "url": "https://github.com/netty/netty/releases/tag/netty-4.1.135.Final"
    },
    {
      "source": "security-advisories@github.com",
      "tags": [
        "Release Notes"
      ],
      "url": "https://github.com/netty/netty/releases/tag/netty-4.2.15.Final"
    },
    {
      "source": "security-advisories@github.com",
      "tags": [
        "Vendor Advisory"
      ],
      "url": "https://github.com/netty/netty/security/advisories/GHSA-hvcg-qmg6-jm4c"
    },
    {
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "tags": [
        "Vendor Advisory"
      ],
      "url": "https://github.com/netty/netty/security/advisories/GHSA-hvcg-qmg6-jm4c"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-444"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Secondary"
    }
  ]
}



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