ubuntu-cve-2021-28861
Vulnerability from osv_ubuntu
Published
2022-08-23 01:15
Modified
2026-04-22 07:39
Summary
Details

Python 3.x through 3.10 has an open redirection vulnerability in lib/http/server.py due to no protection against multiple (/) at the beginning of URI path which may leads to information disclosure. NOTE: this is disputed by a third party because the http.server.html documentation page states "Warning: http.server is not recommended for production. It only implements basic security checks."

Severity
7.4 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:N/A:N
6.5 (Medium)
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
N/A (UNKNOWN)
low
References
To clipboard 

{
  "affected": [
    {
      "ecosystem_specific": {
        "availability": "Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro",
        "binaries": [
          {
            "binary_name": "idle-python3.5",
            "binary_version": "3.5.2-2ubuntu0~16.04.13+esm5"
          },
          {
            "binary_name": "libpython3.5",
            "binary_version": "3.5.2-2ubuntu0~16.04.13+esm5"
          },
          {
            "binary_name": "libpython3.5-minimal",
            "binary_version": "3.5.2-2ubuntu0~16.04.13+esm5"
          },
          {
            "binary_name": "libpython3.5-stdlib",
            "binary_version": "3.5.2-2ubuntu0~16.04.13+esm5"
          },
          {
            "binary_name": "libpython3.5-testsuite",
            "binary_version": "3.5.2-2ubuntu0~16.04.13+esm5"
          },
          {
            "binary_name": "python3.5",
            "binary_version": "3.5.2-2ubuntu0~16.04.13+esm5"
          },
          {
            "binary_name": "python3.5-examples",
            "binary_version": "3.5.2-2ubuntu0~16.04.13+esm5"
          },
          {
            "binary_name": "python3.5-minimal",
            "binary_version": "3.5.2-2ubuntu0~16.04.13+esm5"
          },
          {
            "binary_name": "python3.5-venv",
            "binary_version": "3.5.2-2ubuntu0~16.04.13+esm5"
          }
        ],
        "priority_reason": "Works as documented, and disputed as being a security issue"
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:16.04:LTS",
        "name": "python3.5",
        "purl": "pkg:deb/ubuntu/python3.5@3.5.2-2ubuntu0~16.04.13+esm5?arch=source\u0026distro=esm-infra/xenial"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "3.5.2-2ubuntu0~16.04.13+esm5"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "3.5.0-3",
        "3.5.0-3ubuntu1",
        "3.5.1~rc1-2ubuntu1",
        "3.5.1-1",
        "3.5.1-2",
        "3.5.1-3",
        "3.5.1-5",
        "3.5.1-6ubuntu1",
        "3.5.1-6ubuntu2",
        "3.5.1-9ubuntu1",
        "3.5.1-10",
        "3.5.2-2~16.01",
        "3.5.2-2~16.04",
        "3.5.2-2ubuntu0~16.04.1",
        "3.5.2-2ubuntu0~16.04.2",
        "3.5.2-2ubuntu0~16.04.3",
        "3.5.2-2ubuntu0~16.04.4",
        "3.5.2-2ubuntu0~16.04.5",
        "3.5.2-2ubuntu0~16.04.8",
        "3.5.2-2ubuntu0~16.04.9",
        "3.5.2-2ubuntu0~16.04.10",
        "3.5.2-2ubuntu0~16.04.11",
        "3.5.2-2ubuntu0~16.04.12",
        "3.5.2-2ubuntu0~16.04.13",
        "3.5.2-2ubuntu0~16.04.13+esm1",
        "3.5.2-2ubuntu0~16.04.13+esm2",
        "3.5.2-2ubuntu0~16.04.13+esm3"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "Available with Ubuntu Pro: https://ubuntu.com/pro",
        "binaries": [
          {
            "binary_name": "idle-python3.9",
            "binary_version": "3.9.5-3ubuntu0~20.04.1+esm1"
          },
          {
            "binary_name": "libpython3.9",
            "binary_version": "3.9.5-3ubuntu0~20.04.1+esm1"
          },
          {
            "binary_name": "libpython3.9-minimal",
            "binary_version": "3.9.5-3ubuntu0~20.04.1+esm1"
          },
          {
            "binary_name": "libpython3.9-stdlib",
            "binary_version": "3.9.5-3ubuntu0~20.04.1+esm1"
          },
          {
            "binary_name": "libpython3.9-testsuite",
            "binary_version": "3.9.5-3ubuntu0~20.04.1+esm1"
          },
          {
            "binary_name": "python3.9",
            "binary_version": "3.9.5-3ubuntu0~20.04.1+esm1"
          },
          {
            "binary_name": "python3.9-examples",
            "binary_version": "3.9.5-3ubuntu0~20.04.1+esm1"
          },
          {
            "binary_name": "python3.9-full",
            "binary_version": "3.9.5-3ubuntu0~20.04.1+esm1"
          },
          {
            "binary_name": "python3.9-minimal",
            "binary_version": "3.9.5-3ubuntu0~20.04.1+esm1"
          },
          {
            "binary_name": "python3.9-venv",
            "binary_version": "3.9.5-3ubuntu0~20.04.1+esm1"
          }
        ],
        "priority_reason": "Works as documented, and disputed as being a security issue"
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:20.04:LTS",
        "name": "python3.9",
        "purl": "pkg:deb/ubuntu/python3.9@3.9.5-3ubuntu0~20.04.1+esm1?arch=source\u0026distro=esm-apps/focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "3.9.5-3ubuntu0~20.04.1+esm1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "3.9.0~rc1-1~20.04",
        "3.9.0-5~20.04",
        "3.9.5-3~20.04.1",
        "3.9.5-3ubuntu0~20.04.1"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "idle-python3.10",
            "binary_version": "3.10.6-1~22.04.1"
          },
          {
            "binary_name": "libpython3.10",
            "binary_version": "3.10.6-1~22.04.1"
          },
          {
            "binary_name": "libpython3.10-minimal",
            "binary_version": "3.10.6-1~22.04.1"
          },
          {
            "binary_name": "libpython3.10-stdlib",
            "binary_version": "3.10.6-1~22.04.1"
          },
          {
            "binary_name": "libpython3.10-testsuite",
            "binary_version": "3.10.6-1~22.04.1"
          },
          {
            "binary_name": "python3.10",
            "binary_version": "3.10.6-1~22.04.1"
          },
          {
            "binary_name": "python3.10-examples",
            "binary_version": "3.10.6-1~22.04.1"
          },
          {
            "binary_name": "python3.10-full",
            "binary_version": "3.10.6-1~22.04.1"
          },
          {
            "binary_name": "python3.10-minimal",
            "binary_version": "3.10.6-1~22.04.1"
          },
          {
            "binary_name": "python3.10-nopie",
            "binary_version": "3.10.6-1~22.04.1"
          },
          {
            "binary_name": "python3.10-venv",
            "binary_version": "3.10.6-1~22.04.1"
          }
        ],
        "priority_reason": "Works as documented, and disputed as being a security issue"
      },
      "package": {
        "ecosystem": "Ubuntu:22.04:LTS",
        "name": "python3.10",
        "purl": "pkg:deb/ubuntu/python3.10@3.10.6-1~22.04.1?arch=source\u0026distro=jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "3.10.6-1~22.04.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "3.10.0-2",
        "3.10.0-3",
        "3.10.0-4",
        "3.10.0-5",
        "3.10.0-5build1",
        "3.10.1-1",
        "3.10.1-2",
        "3.10.2-1",
        "3.10.2-5",
        "3.10.2-7",
        "3.10.3-1",
        "3.10.4-3",
        "3.10.4-3ubuntu0.1",
        "3.10.6-1~22.04"
      ]
    }
  ],
  "aliases": [],
  "details": "Python 3.x through 3.10 has an open redirection vulnerability in lib/http/server.py due to no protection against multiple (/) at the beginning of URI path which may leads to information disclosure. NOTE: this is disputed by a third party because the http.server.html documentation page states \"Warning: http.server is not recommended for production. It only implements basic security checks.\"",
  "id": "UBUNTU-CVE-2021-28861",
  "modified": "2026-04-22T07:39:58Z",
  "published": "2022-08-23T01:15:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2021-28861"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/python/cpython/pull/93879"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/python/cpython/pull/24848"
    },
    {
      "type": "ADVISORY",
      "url": "https://ubuntu.com/security/notices/USN-5629-1"
    },
    {
      "type": "ADVISORY",
      "url": "https://ubuntu.com/security/notices/USN-5888-1"
    },
    {
      "type": "REPORT",
      "url": "https://python-security.readthedocs.io/vuln/http-server-redirection.html"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2021-28861"
    }
  ],
  "related": [
    "USN-5629-1",
    "USN-5888-1"
  ],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:N/A:N",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N",
      "type": "CVSS_V3"
    },
    {
      "score": "low",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2021-28861"
  ]
}



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Sightings

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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.


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