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CVE-2026-20343 (GCVE-0-2026-20343)

Vulnerability from cvelistv5 – Published: 2026-09-16 20:12 – Updated: 2026-09-16 20:12
VLAI
Title
Cisco Secure Firewall Management Center Software Information Disclosure and Disk Denial of Service Vulnerability
Summary
A vulnerability in a critical API for Cisco Secure FMC Software could allow an unauthenticated, remote attacker to download sensitive files and use unbounded disk space. This vulnerability exists because a critical API lacks authentication. An attacker could exploit this vulnerability by repeatedly invoking the API. A successful exploit could allow the attacker to download sensitive files that should be restricted and consume disk space so the device could become unresponsive, causing a DoS condition.
Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CWE
  • CWE-306 - Missing Authentication for Critical Function
Assigner
References
Impacted products
Vendor Product Version CPE status
Cisco Cisco Secure Firewall Management Center (FMC) Affected: 7.3.0
Affected: 7.3.1
Affected: 7.3.1.1
Affected: 7.4.0
Affected: 7.4.1
Affected: 7.4.1.1
Affected: 7.3.1.2
Affected: 7.6.0
Affected: 7.4.2
Affected: 7.4.2.1
Affected: 7.7.0
Affected: 7.4.2.2
Affected: 7.6.1
Affected: 7.4.2.3
Affected: 7.6.2
Affected: 7.7.10
Affected: 7.6.2.1
Affected: 7.7.10.1
Affected: 7.4.2.4
Affected: 7.4.3
Affected: 7.6.3
Affected: 7.7.11
Affected: 7.6.4
Affected: 10.0.0
Affected: 7.4.4
Affected: 7.4.5
Affected: 7.7.12
Affected: 7.6.5
Affected: 7.4.6
Affected: 10.0.1
Affected: 7.4.7
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unknown",
          "product": "Cisco Secure Firewall Management Center (FMC)",
          "vendor": "Cisco",
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            },
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              "status": "affected",
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            },
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              "status": "affected",
              "version": "7.3.1.1"
            },
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              "version": "7.4.0"
            },
            {
              "status": "affected",
              "version": "7.4.1"
            },
            {
              "status": "affected",
              "version": "7.4.1.1"
            },
            {
              "status": "affected",
              "version": "7.3.1.2"
            },
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              "status": "affected",
              "version": "7.6.0"
            },
            {
              "status": "affected",
              "version": "7.4.2"
            },
            {
              "status": "affected",
              "version": "7.4.2.1"
            },
            {
              "status": "affected",
              "version": "7.7.0"
            },
            {
              "status": "affected",
              "version": "7.4.2.2"
            },
            {
              "status": "affected",
              "version": "7.6.1"
            },
            {
              "status": "affected",
              "version": "7.4.2.3"
            },
            {
              "status": "affected",
              "version": "7.6.2"
            },
            {
              "status": "affected",
              "version": "7.7.10"
            },
            {
              "status": "affected",
              "version": "7.6.2.1"
            },
            {
              "status": "affected",
              "version": "7.7.10.1"
            },
            {
              "status": "affected",
              "version": "7.4.2.4"
            },
            {
              "status": "affected",
              "version": "7.4.3"
            },
            {
              "status": "affected",
              "version": "7.6.3"
            },
            {
              "status": "affected",
              "version": "7.7.11"
            },
            {
              "status": "affected",
              "version": "7.6.4"
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            {
              "status": "affected",
              "version": "10.0.0"
            },
            {
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              "version": "7.4.4"
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            {
              "status": "affected",
              "version": "7.4.5"
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            {
              "status": "affected",
              "version": "7.7.12"
            },
            {
              "status": "affected",
              "version": "7.6.5"
            },
            {
              "status": "affected",
              "version": "7.4.6"
            },
            {
              "status": "affected",
              "version": "10.0.1"
            },
            {
              "status": "affected",
              "version": "7.4.7"
            }
          ]
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        }
      ],
      "exploits": [
        {
          "lang": "en",
          "value": "The Cisco Product Security Incident Response Team (PSIRT) is not aware of any public announcements or malicious use of the vulnerabilities that are described in this advisory."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "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"
          },
          "format": "cvssV3_1"
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-306",
              "description": "Missing Authentication for Critical Function",
              "lang": "en",
              "type": "cwe"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-16T20:12:19.940Z",
        "orgId": "d1c1063e-7a18-46af-9102-31f8928bc633",
        "shortName": "cisco"
      },
      "references": [
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          "name": "cisco-sa-fmc-mulivulns-4PsnFwvx",
          "url": "https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-fmc-mulivulns-4PsnFwvx"
        }
      ],
      "source": {
        "advisory": "cisco-sa-fmc-mulivulns-4PsnFwvx",
        "defects": [
          "CSCwu36643"
        ],
        "discovery": "INTERNAL"
      },
      "title": "Cisco Secure Firewall Management Center Software Information Disclosure and Disk Denial of Service Vulnerability"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "d1c1063e-7a18-46af-9102-31f8928bc633",
    "assignerShortName": "cisco",
    "cveId": "CVE-2026-20343",
    "datePublished": "2026-09-16T20:12:19.940Z",
    "dateReserved": "2025-10-08T11:59:15.413Z",
    "dateUpdated": "2026-09-16T20:12:19.940Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-20343",
      "date": "2026-09-17",
      "epss": "0.0045",
      "percentile": "0.38328"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-20343\",\"sourceIdentifier\":\"psirt@cisco.com\",\"published\":\"2026-09-16T21:17:11.850\",\"lastModified\":\"2026-09-16T21:17:11.850\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"A vulnerability in a critical API for Cisco Secure FMC Software could allow an unauthenticated, remote attacker to download sensitive files and use unbounded disk space.\\r\\n\\r\\nThis vulnerability exists because a critical API lacks authentication.\u0026nbsp;An attacker could exploit this vulnerability by repeatedly invoking the API. A successful exploit could allow the attacker to download sensitive files that should be restricted and consume disk space so the device could become unresponsive, causing a DoS condition.\"}],\"affected\":[{\"source\":\"psirt@cisco.com\",\"affectedData\":[{\"vendor\":\"Cisco\",\"product\":\"Cisco Secure Firewall Management Center (FMC)\",\"defaultStatus\":\"unknown\",\"versions\":[{\"version\":\"7.3.0\",\"status\":\"affected\"},{\"version\":\"7.3.1\",\"status\":\"affected\"},{\"version\":\"7.3.1.1\",\"status\":\"affected\"},{\"version\":\"7.4.0\",\"status\":\"affected\"},{\"version\":\"7.4.1\",\"status\":\"affected\"},{\"version\":\"7.4.1.1\",\"status\":\"affected\"},{\"version\":\"7.3.1.2\",\"status\":\"affected\"},{\"version\":\"7.6.0\",\"status\":\"affected\"},{\"version\":\"7.4.2\",\"status\":\"affected\"},{\"version\":\"7.4.2.1\",\"status\":\"affected\"},{\"version\":\"7.7.0\",\"status\":\"affected\"},{\"version\":\"7.4.2.2\",\"status\":\"affected\"},{\"version\":\"7.6.1\",\"status\":\"affected\"},{\"version\":\"7.4.2.3\",\"status\":\"affected\"},{\"version\":\"7.6.2\",\"status\":\"affected\"},{\"version\":\"7.7.10\",\"status\":\"affected\"},{\"version\":\"7.6.2.1\",\"status\":\"affected\"},{\"version\":\"7.7.10.1\",\"status\":\"affected\"},{\"version\":\"7.4.2.4\",\"status\":\"affected\"},{\"version\":\"7.4.3\",\"status\":\"affected\"},{\"version\":\"7.6.3\",\"status\":\"affected\"},{\"version\":\"7.7.11\",\"status\":\"affected\"},{\"version\":\"7.6.4\",\"status\":\"affected\"},{\"version\":\"10.0.0\",\"status\":\"affected\"},{\"version\":\"7.4.4\",\"status\":\"affected\"},{\"version\":\"7.4.5\",\"status\":\"affected\"},{\"version\":\"7.7.12\",\"status\":\"affected\"},{\"version\":\"7.6.5\",\"status\":\"affected\"},{\"version\":\"7.4.6\",\"status\":\"affected\"},{\"version\":\"10.0.1\",\"status\":\"affected\"},{\"version\":\"7.4.7\",\"status\":\"affected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"psirt@cisco.com\",\"type\":\"Primary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H\",\"baseScore\":7.5,\"baseSeverity\":\"HIGH\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"NONE\",\"integrityImpact\":\"NONE\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":3.9,\"impactScore\":3.6}]},\"weaknesses\":[{\"source\":\"psirt@cisco.com\",\"type\":\"Primary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-306\"}]}],\"references\":[{\"url\":\"https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-fmc-mulivulns-4PsnFwvx\",\"source\":\"psirt@cisco.com\"}]}}"
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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.
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  • 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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Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.