ubuntu-cve-2021-21290
Vulnerability from osv_ubuntu
Published
2021-02-08 20:15
Modified
2026-06-08 16:09
Summary
Details

Netty is an open-source, asynchronous event-driven network application framework for rapid development of maintainable high performance protocol servers & clients. In Netty before version 4.1.59.Final there is a vulnerability on Unix-like systems involving an insecure temp file. When netty's multipart decoders are used local information disclosure can occur via the local system temporary directory if temporary storing uploads on the disk is enabled. On unix-like systems, the temporary directory is shared between all user. As such, writing to this directory using APIs that do not explicitly set the file/directory permissions can lead to information disclosure. Of note, this does not impact modern MacOS Operating Systems. The method "File.createTempFile" on unix-like systems creates a random file, but, by default will create this file with the permissions "-rw-r--r--". Thus, if sensitive information is written to this file, other local users can read this information. This is the case in netty's "AbstractDiskHttpData" is vulnerable. This has been fixed in version 4.1.59.Final. As a workaround, one may specify your own "java.io.tmpdir" when you start the JVM or use "DefaultHttpDataFactory.setBaseDir(...)" to set the directory to something that is only readable by the current user.

Severity
6.2 (Medium)
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
5.5 (Medium)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
N/A (UNKNOWN)
medium
References
To clipboard 

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libnetty-java",
            "binary_version": "1:3.2.6.Final-2+deb8u2ubuntu0.1~esm1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:14.04:LTS",
        "name": "netty",
        "purl": "pkg:deb/ubuntu/netty@1:3.2.6.Final-2+deb8u2ubuntu0.1~esm1?arch=source\u0026distro=esm-infra-legacy/trusty"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1:3.2.6.Final-2",
        "1:3.2.6.Final-2+deb8u2build0.14.04.1~esm1",
        "1:3.2.6.Final-2+deb8u2ubuntu0.1~esm1"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "Available with Ubuntu Pro: https://ubuntu.com/pro",
        "binaries": [
          {
            "binary_name": "libnetty-java",
            "binary_version": "1:4.0.34-1ubuntu0.1~esm1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:16.04:LTS",
        "name": "netty",
        "purl": "pkg:deb/ubuntu/netty@1:4.0.34-1ubuntu0.1~esm1?arch=source\u0026distro=esm-apps/xenial"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1:4.0.34-1ubuntu0.1~esm1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1:3.2.6.Final-2",
        "1:4.0.32-1",
        "1:4.0.33-1",
        "1:4.0.34-1"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "Available with Ubuntu Pro: https://ubuntu.com/pro",
        "binaries": [
          {
            "binary_name": "libnetty-java",
            "binary_version": "1:4.1.7-4ubuntu0.1+esm2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:18.04:LTS",
        "name": "netty",
        "purl": "pkg:deb/ubuntu/netty@1:4.1.7-4ubuntu0.1+esm2?arch=source\u0026distro=esm-apps/bionic"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1:4.1.7-4ubuntu0.1+esm2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1:4.1.7-4",
        "1:4.1.7-4ubuntu0.1~esm1",
        "1:4.1.7-4ubuntu0.1",
        "1:4.1.7-4ubuntu0.1+esm1"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "Available with Ubuntu Pro: https://ubuntu.com/pro",
        "binaries": [
          {
            "binary_name": "libnetty-java",
            "binary_version": "1:4.1.45-1ubuntu0.1~esm1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:20.04:LTS",
        "name": "netty",
        "purl": "pkg:deb/ubuntu/netty@1:4.1.45-1ubuntu0.1~esm1?arch=source\u0026distro=esm-apps/focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1:4.1.45-1ubuntu0.1~esm1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1:4.1.33-1",
        "1:4.1.33-2",
        "1:4.1.33-3",
        "1:4.1.45-1"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "libnetty-java",
            "binary_version": "1:4.1.48-4+deb11u1build0.22.04.1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:22.04:LTS",
        "name": "netty",
        "purl": "pkg:deb/ubuntu/netty@1:4.1.48-4+deb11u1build0.22.04.1?arch=source\u0026distro=jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1:4.1.48-4+deb11u1build0.22.04.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1:4.1.48-4"
      ]
    }
  ],
  "aliases": [],
  "details": "Netty is an open-source, asynchronous event-driven network application framework for rapid development of maintainable high performance protocol servers \u0026 clients. In Netty before version 4.1.59.Final there is a vulnerability on Unix-like systems involving an insecure temp file. When netty\u0027s multipart decoders are used local information disclosure can occur via the local system temporary directory if temporary storing uploads on the disk is enabled. On unix-like systems, the temporary directory is shared between all user. As such, writing to this directory using APIs that do not explicitly set the file/directory permissions can lead to information disclosure. Of note, this does not impact modern MacOS Operating Systems. The method \"File.createTempFile\" on unix-like systems creates a random file, but, by default will create this file with the permissions \"-rw-r--r--\". Thus, if sensitive information is written to this file, other local users can read this information. This is the case in netty\u0027s \"AbstractDiskHttpData\" is vulnerable. This has been fixed in version 4.1.59.Final. As a workaround, one may specify your own \"java.io.tmpdir\" when you start the JVM or use \"DefaultHttpDataFactory.setBaseDir(...)\" to set the directory to something that is only readable by the current user.",
  "id": "UBUNTU-CVE-2021-21290",
  "modified": "2026-06-08T16:09:12Z",
  "published": "2021-02-08T20:15:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2021-21290"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/netty/netty/commit/c735357bf29d07856ad171c6611a2e1a0e0000ec"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/netty/netty/security/advisories/GHSA-5mcr-gq6c-3hq2"
    },
    {
      "type": "ADVISORY",
      "url": "https://ubuntu.com/security/notices/USN-6049-1"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2021-21290"
    }
  ],
  "related": [
    "USN-6049-1"
  ],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N",
      "type": "CVSS_V3"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2021-21290"
  ]
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.