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GHSA-MMHR-MFJP-VV8J

Vulnerability from github – Published: 2026-03-30 15:32 – Updated: 2026-03-30 15:32

Details

Note, this vulnerability does not affect Firebox platforms that do not support the Access Portal feature, including the T-15 and T-35.

Severity ?

8.4 (High)


                  
                    CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

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JSON

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{
  "affected": [],
  "aliases": [
    "CVE-2026-4266"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-502"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-03-30T13:16:22Z",
    "severity": "HIGH"
  },
  "details": "An Insecure Deserialization vulnerability in WatchGuard Fireware OS allows an attacker that has obtained write access to the local filesystem through another vulnerability to execute arbitrary code in the context of the portald user.This issue affects Fireware OS: 12.1 through 12.11.8 and 2025.1 through 2026.1.2.\n\nNote, this vulnerability does not affect Firebox platforms that do not support the Access Portal feature, including the T-15 and T-35.",
  "id": "GHSA-mmhr-mfjp-vv8j",
  "modified": "2026-03-30T15:32:05Z",
  "published": "2026-03-30T15:32:05Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-4266"
    },
    {
      "type": "WEB",
      "url": "https://www.watchguard.com/wgrd-psirt/advisory/wgsa-2026-00007"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
      "type": "CVSS_V4"
    }
  ]
}

CVE-2026-4266 (GCVE-0-2026-4266)

Vulnerability from cvelistv5 – Published: 2026-03-30 12:38 – Updated: 2026-03-31 03:55

Title

WatchGuard Firebox Insecure Deserialization in Fireware Access Portal

Summary

An Insecure Deserialization vulnerability in WatchGuard Fireware OS allows an attacker that has obtained write access to the local filesystem through another vulnerability to execute arbitrary code in the context of the portald user.This issue affects Fireware OS: 12.1 through 12.11.8 and 2025.1 through 2026.1.2. Note, this vulnerability does not affect Firebox platforms that do not support the Access Portal feature, including the T-15 and T-35.

Severity ?

8.4 (High)


                        
                          CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

CWE

CWE-502 - Deserialization of Untrusted Data

Assigner

WatchGuard

References

URL

Tags

https://www.watchguard.com/wgrd-psirt/advisory/wg…

vendor-advisory

Impacted products

	Vendor	Product	Version
	WatchGuard	Fireware OS	Affected: 12.1 , ≤ 12.11.8 (semver) Affected: 2025.1 , ≤ 2026.1.2 (semver)

Credits

btaol

Show details on NVD website

JSON

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  "containers": {
    "adp": [
      {
        "metrics": [
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            "other": {
              "content": {
                "id": "CVE-2026-4266",
                "options": [
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                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-03-30T00:00:00+00:00",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-03-31T03:55:35.825Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
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          "product": "Fireware OS",
          "vendor": "WatchGuard",
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              "status": "affected",
              "version": "12.1",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "2026.1.2",
              "status": "affected",
              "version": "2025.1",
              "versionType": "semver"
            }
          ]
        }
      ],
      "cpeApplicability": [
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          "nodes": [
            {
              "cpeMatch": [
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                  "criteria": "cpe:2.3:a:watchguard:fireware_os:*:*:*:*:*:*:*:12.1",
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                  "vulnerable": true
                },
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                  "versionStartIncluding": "2025.1",
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          ],
          "operator": "OR"
        }
      ],
      "credits": [
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          "lang": "en",
          "type": "finder",
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        }
      ],
      "descriptions": [
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          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "An Insecure Deserialization vulnerability in WatchGuard Fireware OS allows an attacker that has obtained write access to the local filesystem through another vulnerability to execute arbitrary code in the context of the portald user.\u003cp\u003eThis issue affects Fireware OS: 12.1 through 12.11.8 and 2025.1 through 2026.1.2.\u003cbr\u003e\u003cbr\u003eNote, this vulnerability does not affect Firebox platforms that do not support the Access Portal feature, including the T-15 and T-35.\u003c/p\u003e"
            }
          ],
          "value": "An Insecure Deserialization vulnerability in WatchGuard Fireware OS allows an attacker that has obtained write access to the local filesystem through another vulnerability to execute arbitrary code in the context of the portald user.This issue affects Fireware OS: 12.1 through 12.11.8 and 2025.1 through 2026.1.2.\n\nNote, this vulnerability does not affect Firebox platforms that do not support the Access Portal feature, including the T-15 and T-35."
        }
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      "exploits": [
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          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "WatchGuard is not aware of any exploitation of this issue in the wild.\u003cbr\u003e"
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          ],
          "value": "WatchGuard is not aware of any exploitation of this issue in the wild."
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      ],
      "impacts": [
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          "capecId": "CAPEC-253",
          "descriptions": [
            {
              "lang": "en",
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      "metrics": [
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            "Recovery": "NOT_DEFINED",
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            "userInteraction": "NONE",
            "valueDensity": "NOT_DEFINED",
            "vectorString": "CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N",
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            "vulnAvailabilityImpact": "HIGH",
            "vulnConfidentialityImpact": "HIGH",
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          "scenarios": [
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        "orgId": "5d1c2695-1a31-4499-88ae-e847036fd7e3",
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      ],
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        "defect": [
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        "discovery": "EXTERNAL"
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    "assignerOrgId": "5d1c2695-1a31-4499-88ae-e847036fd7e3",
    "assignerShortName": "WatchGuard",
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    "datePublished": "2026-03-30T12:38:01.593Z",
    "dateReserved": "2026-03-16T12:50:10.806Z",
    "dateUpdated": "2026-03-31T03:55:35.825Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date

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.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
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.

Detection rules are retrieved from Rulezet.

Action not permitted

GHSA-MMHR-MFJP-VV8J

CVE-2026-4266 (GCVE-0-2026-4266)

Tags

Sightings

Nomenclature