CVE-2026-4701 (GCVE-0-2026-4701)

Vulnerability from cvelistv5 – Published: 2026-03-24 12:30 – Updated: 2026-05-12 16:54
VLAI
Title
Use-after-free in the JavaScript Engine component
Summary
Use-after-free in the JavaScript Engine component. This vulnerability was fixed in Firefox 149, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9.
Severity
9.8 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CWE
Assigner
References
Impacted products
Vendor Product Version
Mozilla Firefox Unaffected: 140.9 , ≤ 140.* (rpm)
Unaffected: 149 , ≤ * (rpm)
Create a notification for this product.
Mozilla Thunderbird Unaffected: 140.9 , ≤ 140.* (rpm)
Unaffected: 149 , ≤ * (rpm)
Create a notification for this product.
Credits
Gary Kwong
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "cvssV3_1": {
              "attackComplexity": "LOW",
              "attackVector": "NETWORK",
              "availabilityImpact": "HIGH",
              "baseScore": 9.8,
              "baseSeverity": "CRITICAL",
              "confidentialityImpact": "HIGH",
              "integrityImpact": "HIGH",
              "privilegesRequired": "NONE",
              "scope": "UNCHANGED",
              "userInteraction": "NONE",
              "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
              "version": "3.1"
            }
          },
          {
            "other": {
              "content": {
                "id": "CVE-2026-4701",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-03-26T13:04:34.007549Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "problemTypes": [
          {
            "descriptions": [
              {
                "cweId": "CWE-416",
                "description": "CWE-416 Use After Free",
                "lang": "en",
                "type": "CWE"
              }
            ]
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-05-12T16:54:17.477Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "Firefox",
          "vendor": "Mozilla",
          "versions": [
            {
              "lessThanOrEqual": "140.*",
              "status": "unaffected",
              "version": "140.9",
              "versionType": "rpm"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "149",
              "versionType": "rpm"
            }
          ]
        },
        {
          "product": "Thunderbird",
          "vendor": "Mozilla",
          "versions": [
            {
              "lessThanOrEqual": "140.*",
              "status": "unaffected",
              "version": "140.9",
              "versionType": "rpm"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "149",
              "versionType": "rpm"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "value": "Gary Kwong"
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "Use-after-free in the JavaScript Engine component. This vulnerability was fixed in Firefox 149, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9."
            }
          ],
          "value": "Use-after-free in the JavaScript Engine component. This vulnerability was fixed in Firefox 149, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-04-13T13:50:19.589Z",
        "orgId": "f16b083a-5664-49f3-a51e-8d479e5ed7fe",
        "shortName": "mozilla"
      },
      "references": [
        {
          "url": "https://bugzilla.mozilla.org/show_bug.cgi?id=2009303"
        },
        {
          "url": "https://www.mozilla.org/security/advisories/mfsa2026-20/"
        },
        {
          "url": "https://www.mozilla.org/security/advisories/mfsa2026-22/"
        },
        {
          "url": "https://www.mozilla.org/security/advisories/mfsa2026-23/"
        },
        {
          "url": "https://www.mozilla.org/security/advisories/mfsa2026-24/"
        }
      ],
      "title": "Use-after-free in the JavaScript Engine component"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "f16b083a-5664-49f3-a51e-8d479e5ed7fe",
    "assignerShortName": "mozilla",
    "cveId": "CVE-2026-4701",
    "datePublished": "2026-03-24T12:30:29.700Z",
    "dateReserved": "2026-03-23T23:22:05.456Z",
    "dateUpdated": "2026-05-12T16:54:17.477Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-4701",
      "date": "2026-05-30",
      "epss": "0.00025",
      "percentile": "0.07484"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-4701\",\"sourceIdentifier\":\"security@mozilla.org\",\"published\":\"2026-03-24T13:16:06.103\",\"lastModified\":\"2026-04-13T15:17:39.750\",\"vulnStatus\":\"Modified\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"Use-after-free in the JavaScript Engine component. This vulnerability was fixed in Firefox 149, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9.\"},{\"lang\":\"es\",\"value\":\"Uso despu\u00e9s de liberaci\u00f3n en el componente del motor JavaScript. Esta vulnerabilidad afecta a Firefox \u0026lt; 149, Firefox ESR \u0026lt; 140.9, Thunderbird \u0026lt; 149, y Thunderbird \u0026lt; 140.9.\"}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"nvd@nist.gov\",\"type\":\"Primary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H\",\"baseScore\":9.8,\"baseSeverity\":\"CRITICAL\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":3.9,\"impactScore\":5.9},{\"source\":\"134c704f-9b21-4f2e-91b3-4a467353bcc0\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H\",\"baseScore\":9.8,\"baseSeverity\":\"CRITICAL\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":3.9,\"impactScore\":5.9}]},\"weaknesses\":[{\"source\":\"nvd@nist.gov\",\"type\":\"Primary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-416\"}]},{\"source\":\"134c704f-9b21-4f2e-91b3-4a467353bcc0\",\"type\":\"Secondary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-416\"}]}],\"configurations\":[{\"nodes\":[{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":true,\"criteria\":\"cpe:2.3:a:mozilla:firefox:*:*:*:*:esr:*:*:*\",\"versionEndExcluding\":\"140.9.0\",\"matchCriteriaId\":\"DA62D95E-CB01-4586-83DB-5094116FC939\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:*\",\"versionEndExcluding\":\"149.0\",\"matchCriteriaId\":\"02F2B82F-E997-4D5F-BBB0-237E4962555B\"}]}]}],\"references\":[{\"url\":\"https://bugzilla.mozilla.org/show_bug.cgi?id=2009303\",\"source\":\"security@mozilla.org\",\"tags\":[\"Permissions Required\"]},{\"url\":\"https://www.mozilla.org/security/advisories/mfsa2026-20/\",\"source\":\"security@mozilla.org\",\"tags\":[\"Vendor Advisory\"]},{\"url\":\"https://www.mozilla.org/security/advisories/mfsa2026-22/\",\"source\":\"security@mozilla.org\",\"tags\":[\"Vendor Advisory\"]},{\"url\":\"https://www.mozilla.org/security/advisories/mfsa2026-23/\",\"source\":\"security@mozilla.org\"},{\"url\":\"https://www.mozilla.org/security/advisories/mfsa2026-24/\",\"source\":\"security@mozilla.org\"}]}}",
    "vulnrichment": {
      "containers": "{\"adp\": [{\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"cvssV3_1\": {\"scope\": \"UNCHANGED\", \"version\": \"3.1\", \"baseScore\": 9.8, \"attackVector\": \"NETWORK\", \"baseSeverity\": \"CRITICAL\", \"vectorString\": \"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H\", \"integrityImpact\": \"HIGH\", \"userInteraction\": \"NONE\", \"attackComplexity\": \"LOW\", \"availabilityImpact\": \"HIGH\", \"privilegesRequired\": \"NONE\", \"confidentialityImpact\": \"HIGH\"}}, {\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2026-4701\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"yes\"}, {\"Technical Impact\": \"total\"}], \"version\": \"2.0.3\", \"timestamp\": \"2026-03-26T13:04:34.007549Z\"}}}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-416\", \"description\": \"CWE-416 Use After Free\"}]}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2026-03-26T13:05:14.368Z\"}}], \"cna\": {\"title\": \"Use-after-free in the JavaScript Engine component\", \"credits\": [{\"lang\": \"en\", \"value\": \"Gary Kwong\"}], \"affected\": [{\"vendor\": \"Mozilla\", \"product\": \"Firefox\", \"versions\": [{\"status\": \"unaffected\", \"version\": \"140.9\", \"versionType\": \"rpm\", \"lessThanOrEqual\": \"140.*\"}, {\"status\": \"unaffected\", \"version\": \"149\", \"versionType\": \"rpm\", \"lessThanOrEqual\": \"*\"}]}, {\"vendor\": \"Mozilla\", \"product\": \"Thunderbird\", \"versions\": [{\"status\": \"unaffected\", \"version\": \"140.9\", \"versionType\": \"rpm\", \"lessThanOrEqual\": \"140.*\"}, {\"status\": \"unaffected\", \"version\": \"149\", \"versionType\": \"rpm\", \"lessThanOrEqual\": \"*\"}]}], \"references\": [{\"url\": \"https://bugzilla.mozilla.org/show_bug.cgi?id=2009303\"}, {\"url\": \"https://www.mozilla.org/security/advisories/mfsa2026-20/\"}, {\"url\": \"https://www.mozilla.org/security/advisories/mfsa2026-22/\"}, {\"url\": \"https://www.mozilla.org/security/advisories/mfsa2026-23/\"}, {\"url\": \"https://www.mozilla.org/security/advisories/mfsa2026-24/\"}], \"descriptions\": [{\"lang\": \"en\", \"value\": \"Use-after-free in the JavaScript Engine component. This vulnerability was fixed in Firefox 149, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9.\", \"supportingMedia\": [{\"type\": \"text/html\", \"value\": \"Use-after-free in the JavaScript Engine component. This vulnerability was fixed in Firefox 149, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9.\", \"base64\": false}]}], \"providerMetadata\": {\"orgId\": \"f16b083a-5664-49f3-a51e-8d479e5ed7fe\", \"shortName\": \"mozilla\", \"dateUpdated\": \"2026-04-13T13:50:19.589Z\"}}}",
      "cveMetadata": "{\"cveId\": \"CVE-2026-4701\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-04-13T13:50:19.589Z\", \"dateReserved\": \"2026-03-23T23:22:05.456Z\", \"assignerOrgId\": \"f16b083a-5664-49f3-a51e-8d479e5ed7fe\", \"datePublished\": \"2026-03-24T12:30:29.700Z\", \"assignerShortName\": \"mozilla\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





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

Author Source Type Date Other

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.