Security advisory

{
  "id": "19912a1f6e640033d499730abf993b83b1b35d3fe523975ea90a5aff77368f74",
  "url": "https://osv.dev/vulnerability/CVE-2021-27291",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2021-27291",
    "summary": "In pygments 1.1+, fixed in 2.7.4, the lexers used to parse programming languages rely heavily on regular expressions. Some of the regular expressions have exponential or cubic worst-case complexity and are vulnerable to ReDoS. By crafting malicious input, an attacker can cause a denial of service.",
    "evidence": "osv:CVE-2021-27291",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2021-27291",
      "aliases": [
        "CVE-2021-27291",
        "GHSA-pq64-v7f5-gqh8",
        "PYSEC-2021-141"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/pygments/pygments",
              "type": "GIT",
              "events": [
                {
                  "introduced": "f534f990331df660f5a5ea6947943e184672ac51"
                },
                {
                  "fixed": "4d555d0fffc914a2a4ac9874416cdaaf8f8c9e74"
                },
                {
                  "fixed": "2e7e8c4a7b318f4032493773732754e418279a14"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:pygments:pygments:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "1.1"
                      },
                      {
                        "fixed": "2.7.4"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "range": [
                      {
                        "fixed": "2e7e8c4a7b318f4032493773732754e418279a14"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  }
                ]
              }
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-27291.json"
          }
        }
      ],
      "modified": "2026-10-20T10:54:35.504740624Z",
      "provider": "osv",
      "references": [
        "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/GSJRFHALQ7E3UV4FFMFU2YQ6LUDHAI55/",
        "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WSLD67LFGXOX2K5YNESSWAS4AGZIJTUQ/",
        "https://lists.debian.org/debian-lts-announce/2021/03/msg00024.html",
        "https://lists.debian.org/debian-lts-announce/2021/05/msg00003.html",
        "https://lists.debian.org/debian-lts-announce/2021/05/msg00006.html",
        "https://www.debian.org/security/2021/dsa-4878",
        "https://www.debian.org/security/2021/dsa-4889",
        "https://github.com/pygments/pygments/commit/2e7e8c4a7b318f4032493773732754e418279a14",
        "https://gist.github.com/b-c-ds/b1a2cc0c68a35c57188575eb496de5ce"
      ],
      "provider_metadata": {
        "unresolved_ranges": [
          {
            "cpes": [
              "cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*",
              "cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*"
            ],
            "vendor_product": "debian:debian_linux",
            "extracted_events": [
              {
                "range": [
                  {
                    "introduced": "9.0"
                  },
                  {
                    "last_affected": "9.0"
                  },
                  {
                    "introduced": "10.0"
                  },
                  {
                    "last_affected": "10.0"
                  }
                ],
                "source": "CPE_STRING"
              }
            ]
          },
          {
            "cpes": [
              "cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:*",
              "cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*"
            ],
            "vendor_product": "fedoraproject:fedora",
            "extracted_events": [
              {
                "range": [
                  {
                    "introduced": "32"
                  },
                  {
                    "last_affected": "32"
                  },
                  {
                    "introduced": "33"
                  },
                  {
                    "last_affected": "33"
                  }
                ],
                "source": "CPE_STRING"
              }
            ]
          }
        ]
      }
    },
    "related_cves": [
      {
        "value": "CVE-2021-27291",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 385682,
  "published_at": "2021-03-17T13:15:15.137+00:00"
}