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pypy3 — security advisory

Type: advisorySources: OSVAdvisory ID: DEBIAN-CVE-2021-3733

There's a flaw in urllib's AbstractBasicAuthHandler class. An attacker who controls a malicious HTTP server that an HTTP client (such as web browser) connects to, could trigger a Regular Expression Denial of Service (ReDOS) during an authentication request with a specially crafted payload that is sent by the server to the client. The greatest threat that this flaw poses is to application availability.

Products
pypy3
Affected versions
Not specified
Fixed versions
7.3.5+dfsg-2
CVEs
CVE-2021-3733
Confirmed fixed CVEs
Not specified
Updated in this feed
30 Oct 2026, 16:51 UTC · Revision 1

Source evidence

DEBIAN-CVE-2021-3733

core-osv · Original source

Published 10 Mar 2022, 17:42 UTC

There's a flaw in urllib's AbstractBasicAuthHandler class. An attacker who controls a malicious HTTP server that an HTTP client (such as web browser) connects to, could trigger a Regular Expression Denial of Service (ReDOS) during an authentication request with a specially crafted payload that is sent by the server to the client. The greatest threat that this flaw poses is to application availability.

osv:DEBIAN-CVE-2021-3733

pypy3

Fixed versions: 7.3.5+dfsg-2

pypy3

Fixed versions: 7.3.5+dfsg-2

pypy3

Fixed versions: 7.3.5+dfsg-2

Complete source record
{
  "id": "090c4940677b12ea32f136074bd3580627e301e443139a045cc4e73ccdc9a18b",
  "url": "https://osv.dev/vulnerability/DEBIAN-CVE-2021-3733",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "DEBIAN-CVE-2021-3733",
    "summary": "There's a flaw in urllib's AbstractBasicAuthHandler class. An attacker who controls a malicious HTTP server that an HTTP client (such as web browser) connects to, could trigger a Regular Expression Denial of Service (ReDOS) during an authentication request with a specially crafted payload that is sent by the server to the client. The greatest threat that this flaw poses is to application availability.",
    "evidence": "osv:DEBIAN-CVE-2021-3733",
    "products": [
      {
        "name": {
          "value": "pypy3",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "7.3.5+dfsg-2",
            "evidence": "/affected/0/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "pypy3",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "7.3.5+dfsg-2",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "pypy3",
          "evidence": "/affected/2/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "7.3.5+dfsg-2",
            "evidence": "/affected/2/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "medium",
    "structured": {
      "id": "DEBIAN-CVE-2021-3733",
      "aliases": [
        "DEBIAN-CVE-2021-3733"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "7.3.5+dfsg-2"
                }
              ]
            }
          ],
          "package": {
            "name": "pypy3",
            "purl": "pkg:deb/debian/pypy3?arch=source&distro=bookworm",
            "ecosystem": "Debian:12"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2021-3733.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "7.3.5+dfsg-2"
                }
              ]
            }
          ],
          "package": {
            "name": "pypy3",
            "purl": "pkg:deb/debian/pypy3?arch=source&distro=trixie",
            "ecosystem": "Debian:13"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2021-3733.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "7.3.5+dfsg-2"
                }
              ]
            }
          ],
          "package": {
            "name": "pypy3",
            "purl": "pkg:deb/debian/pypy3?arch=source&distro=forky",
            "ecosystem": "Debian:14"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2021-3733.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        }
      ],
      "modified": "2026-10-15T09:47:42.510271475Z",
      "provider": "osv",
      "upstream": [
        "CVE-2021-3733"
      ],
      "references": [
        "https://security-tracker.debian.org/tracker/CVE-2021-3733"
      ]
    },
    "related_cves": [
      {
        "value": "CVE-2021-3733",
        "evidence": "/upstream"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 328429,
  "published_at": "2022-03-10T17:42:59.623+00:00"
}