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CVE-2021-20266

Status: ModifiedMedium (4.9)—

A flaw was found in RPM's hdrblobInit() in lib/header.c. This flaw allows an attacker who can modify the rpmdb to cause an out-of-bounds read. The highest threat from this vulnerability is to system availability.

CVSS

Exploitation probability (EPSS)

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

Affected technologies (2)

Fedoraproject — FedoraRPM — RPM

CWEs

References

Raw JSON (NVD)

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{
  "id": "CVE-2021-20266",
  "cveTags": [],
  "metrics": {
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        "type": "Primary",
        "source": "nvd@nist.gov",
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          "baseScore": 4,
          "accessVector": "NETWORK",
          "vectorString": "AV:N/AC:L/Au:S/C:N/I:N/A:P",
          "authentication": "SINGLE",
          "integrityImpact": "NONE",
          "accessComplexity": "LOW",
          "availabilityImpact": "PARTIAL",
          "confidentialityImpact": "NONE"
        },
        "acInsufInfo": false,
        "impactScore": 2.9,
        "baseSeverity": "MEDIUM",
        "obtainAllPrivilege": false,
        "exploitabilityScore": 8,
        "obtainUserPrivilege": false,
        "obtainOtherPrivilege": false,
        "userInteractionRequired": false
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    "cvssMetricV31": [
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          "baseSeverity": "MEDIUM",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H",
          "integrityImpact": "NONE",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "HIGH",
          "confidentialityImpact": "NONE"
        },
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  "affected": [
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      "source": "secalert@redhat.com",
      "affectedData": [
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          "vendor": "n/a",
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          "versions": [
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            }
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  "published": "2021-04-30T12:15:07.500",
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      "source": "af854a3a-2127-422b-91ae-364da2661108"
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  ],
  "vulnStatus": "Modified",
  "weaknesses": [
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      "type": "Secondary",
      "source": "secalert@redhat.com",
      "description": [
        {
          "lang": "en",
          "value": "CWE-125"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "A flaw was found in RPM's hdrblobInit() in lib/header.c. This flaw allows an attacker who can modify the rpmdb to cause an out-of-bounds read. The highest threat from this vulnerability is to system availability."
    },
    {
      "lang": "es",
      "value": "Se detectó un fallo en RPM en la función hdrblobInit() en el archivo lib/header.c. Este fallo permite a un atacante que puede modificar el rpmdb causar una lectura fuera de límites. La mayor amenaza de esta vulnerabilidad es la disponibilidad del sistema."
    }
  ],
  "lastModified": "2026-06-17T03:33:34.400",
  "configurations": [
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}