FKIE_CVE-2021-44686

Vulnerability from fkie_nvd - Published: 2021-12-07 00:15 - Updated: 2025-11-04 16:15
Severity ?
7.5 (High) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Summary
calibre before 5.32.0 contains a regular expression that is vulnerable to ReDoS (Regular Expression Denial of Service) in html_preprocess_rules in ebooks/conversion/preprocess.py.
References
cve@mitre.orghttps://bugs.launchpad.net/calibre/+bug/1951979Exploit, Issue Tracking, Vendor Advisory
cve@mitre.orghttps://github.com/dwisiswant0/advisory/issues/18Exploit, Issue Tracking, Patch, Third Party Advisory
cve@mitre.orghttps://github.com/kovidgoyal/calibre/compare/v5.31.1...v5.32.0Patch, Third Party Advisory
cve@mitre.orghttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/W7QKFPYJ23KG6WJ5NIYAM4N2NWZCLQGL/
af854a3a-2127-422b-91ae-364da2661108https://bugs.launchpad.net/calibre/+bug/1951979Exploit, Issue Tracking, Vendor Advisory
af854a3a-2127-422b-91ae-364da2661108https://github.com/dwisiswant0/advisory/issues/18Exploit, Issue Tracking, Patch, Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108https://github.com/kovidgoyal/calibre/compare/v5.31.1...v5.32.0Patch, Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108https://lists.debian.org/debian-lts-announce/2024/09/msg00005.html
af854a3a-2127-422b-91ae-364da2661108https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/W7QKFPYJ23KG6WJ5NIYAM4N2NWZCLQGL/
Impacted products
Vendor Product Version
calibre-ebook calibre *
fedoraproject fedora 34
To clipboard 

{
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:calibre-ebook:calibre:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "9318CDD6-0832-47C8-A748-63753C21CEE9",
              "versionEndExcluding": "5.32.0",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    },
    {
      "nodes": [
        {
          "cpeMatch": [
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              "criteria": "cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*",
              "matchCriteriaId": "A930E247-0B43-43CB-98FF-6CE7B8189835",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "calibre before 5.32.0 contains a regular expression that is vulnerable to ReDoS (Regular Expression Denial of Service) in html_preprocess_rules in ebooks/conversion/preprocess.py."
    },
    {
      "lang": "es",
      "value": "calibre versiones anteriores a 5.32.0, contiene una expresi\u00f3n regular que es vulnerable a ReDoS (denegaci\u00f3n de servicio por expresi\u00f3n regular) en html_preprocess_rules en el archivo ebooks/conversion/preprocess.py"
    }
  ],
  "id": "CVE-2021-44686",
  "lastModified": "2025-11-04T16:15:45.927",
  "metrics": {
    "cvssMetricV2": [
      {
        "acInsufInfo": false,
        "baseSeverity": "MEDIUM",
        "cvssData": {
          "accessComplexity": "LOW",
          "accessVector": "NETWORK",
          "authentication": "NONE",
          "availabilityImpact": "PARTIAL",
          "baseScore": 5.0,
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "vectorString": "AV:N/AC:L/Au:N/C:N/I:N/A:P",
          "version": "2.0"
        },
        "exploitabilityScore": 10.0,
        "impactScore": 2.9,
        "obtainAllPrivilege": false,
        "obtainOtherPrivilege": false,
        "obtainUserPrivilege": false,
        "source": "nvd@nist.gov",
        "type": "Primary",
        "userInteractionRequired": false
      }
    ],
    "cvssMetricV31": [
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        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 7.5,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 3.6,
        "source": "nvd@nist.gov",
        "type": "Primary"
      }
    ]
  },
  "published": "2021-12-07T00:15:08.087",
  "references": [
    {
      "source": "cve@mitre.org",
      "tags": [
        "Exploit",
        "Issue Tracking",
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      "url": "https://bugs.launchpad.net/calibre/+bug/1951979"
    },
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    },
    {
      "source": "cve@mitre.org",
      "tags": [
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    },
    {
      "source": "cve@mitre.org",
      "url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/W7QKFPYJ23KG6WJ5NIYAM4N2NWZCLQGL/"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
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    },
    {
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      "tags": [
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    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
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    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "url": "https://lists.debian.org/debian-lts-announce/2024/09/msg00005.html"
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      "url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/W7QKFPYJ23KG6WJ5NIYAM4N2NWZCLQGL/"
    }
  ],
  "sourceIdentifier": "cve@mitre.org",
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-400"
        }
      ],
      "source": "nvd@nist.gov",
      "type": "Primary"
    }
  ]
}


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  • 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.
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Detection rules are retrieved from Rulezet.