CVE-2026-2786 (GCVE-0-2026-2786)

Vulnerability from cvelistv5 – Published: 2026-02-24 13:33 – Updated: 2026-05-10 12:54
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 148, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8.
Severity ?
8.8 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
CWE
Assigner
References
Impacted products
Vendor Product Version
Mozilla Firefox Unaffected: 140.8 , ≤ 140.* (rpm)
Unaffected: 148 , ≤ * (rpm)
Create a notification for this product.
Mozilla Thunderbird Unaffected: 140.8 , ≤ 140.* (rpm)
Unaffected: 148 , ≤ * (rpm)
Create a notification for this product.
Credits
Evyatar Ben Asher, Keane Lucas, Nicholas Carlini, Newton Cheng, Daniel Freeman, Alex Gaynor, and Joel Weinberger using Claude from Anthropic
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "cvssV3_1": {
              "attackComplexity": "LOW",
              "attackVector": "NETWORK",
              "availabilityImpact": "HIGH",
              "baseScore": 8.8,
              "baseSeverity": "HIGH",
              "confidentialityImpact": "HIGH",
              "integrityImpact": "HIGH",
              "privilegesRequired": "NONE",
              "scope": "UNCHANGED",
              "userInteraction": "REQUIRED",
              "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
              "version": "3.1"
            }
          },
          {
            "other": {
              "content": {
                "id": "CVE-2026-2786",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-02-26T20:03:48.457816Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "problemTypes": [
          {
            "descriptions": [
              {
                "cweId": "CWE-416",
                "description": "CWE-416 Use After Free",
                "lang": "en",
                "type": "CWE"
              }
            ]
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-05-10T12:54:19.009Z",
          "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": "140.8",
              "versionType": "rpm"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "148",
              "versionType": "rpm"
            }
          ]
        },
        {
          "product": "Thunderbird",
          "vendor": "Mozilla",
          "versions": [
            {
              "lessThanOrEqual": "140.*",
              "status": "unaffected",
              "version": "140.8",
              "versionType": "rpm"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "148",
              "versionType": "rpm"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "value": "Evyatar Ben Asher, Keane Lucas, Nicholas Carlini, Newton Cheng, Daniel Freeman, Alex Gaynor, and Joel Weinberger using Claude from Anthropic"
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "Use-after-free in the JavaScript Engine component. This vulnerability was fixed in Firefox 148, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8."
            }
          ],
          "value": "Use-after-free in the JavaScript Engine component. This vulnerability was fixed in Firefox 148, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-04-13T13:53:40.663Z",
        "orgId": "f16b083a-5664-49f3-a51e-8d479e5ed7fe",
        "shortName": "mozilla"
      },
      "references": [
        {
          "url": "https://bugzilla.mozilla.org/show_bug.cgi?id=2013612"
        },
        {
          "url": "https://www.mozilla.org/security/advisories/mfsa2026-13/"
        },
        {
          "url": "https://www.mozilla.org/security/advisories/mfsa2026-15/"
        },
        {
          "url": "https://www.mozilla.org/security/advisories/mfsa2026-16/"
        },
        {
          "url": "https://www.mozilla.org/security/advisories/mfsa2026-17/"
        }
      ],
      "title": "Use-after-free in the JavaScript Engine component"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "f16b083a-5664-49f3-a51e-8d479e5ed7fe",
    "assignerShortName": "mozilla",
    "cveId": "CVE-2026-2786",
    "datePublished": "2026-02-24T13:33:18.980Z",
    "dateReserved": "2026-02-19T15:06:24.424Z",
    "dateUpdated": "2026-05-10T12:54:19.009Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-2786",
      "date": "2026-05-21",
      "epss": "0.0002",
      "percentile": "0.05652"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-2786\",\"sourceIdentifier\":\"security@mozilla.org\",\"published\":\"2026-02-24T14:16:27.053\",\"lastModified\":\"2026-05-10T13:16:36.050\",\"vulnStatus\":\"Modified\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"Use-after-free in the JavaScript Engine component. This vulnerability was fixed in Firefox 148, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8.\"},{\"lang\":\"es\",\"value\":\"Uso despu\u00e9s de liberaci\u00f3n en el componente del motor JavaScript. Esta vulnerabilidad afecta a Firefox \u0026lt; 148, Firefox ESR \u0026lt; 140.8, Thunderbird \u0026lt; 148, y Thunderbird \u0026lt; 140.8.\"}],\"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:R/S:U/C:H/I:H/A:H\",\"baseScore\":8.8,\"baseSeverity\":\"HIGH\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"REQUIRED\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":2.8,\"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\":\"140.8.0\",\"matchCriteriaId\":\"7DA5BF3D-3278-43DD-9DD4-C78D7A2C1883\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:*\",\"versionEndExcluding\":\"148.0\",\"matchCriteriaId\":\"3D8676DB-4A12-41A0-A1A5-2DED97287973\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:a:mozilla:thunderbird:*:*:*:*:esr:*:*:*\",\"versionEndExcluding\":\"140.8.0\",\"matchCriteriaId\":\"73228A3D-A71B-497B-A5BA-412FFE9F6F37\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:a:mozilla:thunderbird:*:*:*:*:-:*:*:*\",\"versionEndExcluding\":\"148.0\",\"matchCriteriaId\":\"C5EBE90D-1996-4578-B715-605B24E66C59\"}]}]}],\"references\":[{\"url\":\"https://bugzilla.mozilla.org/show_bug.cgi?id=2013612\",\"source\":\"security@mozilla.org\",\"tags\":[\"Issue Tracking\",\"Permissions Required\"]},{\"url\":\"https://www.mozilla.org/security/advisories/mfsa2026-13/\",\"source\":\"security@mozilla.org\",\"tags\":[\"Vendor Advisory\"]},{\"url\":\"https://www.mozilla.org/security/advisories/mfsa2026-15/\",\"source\":\"security@mozilla.org\",\"tags\":[\"Vendor Advisory\"]},{\"url\":\"https://www.mozilla.org/security/advisories/mfsa2026-16/\",\"source\":\"security@mozilla.org\",\"tags\":[\"Vendor Advisory\"]},{\"url\":\"https://www.mozilla.org/security/advisories/mfsa2026-17/\",\"source\":\"security@mozilla.org\",\"tags\":[\"Vendor Advisory\"]}]}}",
    "vulnrichment": {
      "containers": "{\"adp\": [{\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"cvssV3_1\": {\"scope\": \"UNCHANGED\", \"version\": \"3.1\", \"baseScore\": 8.8, \"attackVector\": \"NETWORK\", \"baseSeverity\": \"HIGH\", \"vectorString\": \"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H\", \"integrityImpact\": \"HIGH\", \"userInteraction\": \"REQUIRED\", \"attackComplexity\": \"LOW\", \"availabilityImpact\": \"HIGH\", \"privilegesRequired\": \"NONE\", \"confidentialityImpact\": \"HIGH\"}}, {\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2026-2786\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"no\"}, {\"Technical Impact\": \"total\"}], \"version\": \"2.0.3\", \"timestamp\": \"2026-02-26T20:03:48.457816Z\"}}}], \"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\": \"2026-02-26T20:04:15.792Z\"}}], \"cna\": {\"title\": \"Use-after-free in the JavaScript Engine component\", \"credits\": [{\"lang\": \"en\", \"value\": \"Evyatar Ben Asher, Keane Lucas, Nicholas Carlini, Newton Cheng, Daniel Freeman, Alex Gaynor, and Joel Weinberger using Claude from Anthropic\"}], \"affected\": [{\"vendor\": \"Mozilla\", \"product\": \"Firefox\", \"versions\": [{\"status\": \"unaffected\", \"version\": \"140.8\", \"versionType\": \"rpm\", \"lessThanOrEqual\": \"140.*\"}, {\"status\": \"unaffected\", \"version\": \"148\", \"versionType\": \"rpm\", \"lessThanOrEqual\": \"*\"}]}, {\"vendor\": \"Mozilla\", \"product\": \"Thunderbird\", \"versions\": [{\"status\": \"unaffected\", \"version\": \"140.8\", \"versionType\": \"rpm\", \"lessThanOrEqual\": \"140.*\"}, {\"status\": \"unaffected\", \"version\": \"148\", \"versionType\": \"rpm\", \"lessThanOrEqual\": \"*\"}]}], \"references\": [{\"url\": \"https://bugzilla.mozilla.org/show_bug.cgi?id=2013612\"}, {\"url\": \"https://www.mozilla.org/security/advisories/mfsa2026-13/\"}, {\"url\": \"https://www.mozilla.org/security/advisories/mfsa2026-15/\"}, {\"url\": \"https://www.mozilla.org/security/advisories/mfsa2026-16/\"}, {\"url\": \"https://www.mozilla.org/security/advisories/mfsa2026-17/\"}], \"descriptions\": [{\"lang\": \"en\", \"value\": \"Use-after-free in the JavaScript Engine component. This vulnerability was fixed in Firefox 148, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8.\", \"supportingMedia\": [{\"type\": \"text/html\", \"value\": \"Use-after-free in the JavaScript Engine component. This vulnerability was fixed in Firefox 148, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8.\", \"base64\": false}]}], \"providerMetadata\": {\"orgId\": \"f16b083a-5664-49f3-a51e-8d479e5ed7fe\", \"shortName\": \"mozilla\", \"dateUpdated\": \"2026-04-13T13:53:40.663Z\"}}}",
      "cveMetadata": "{\"cveId\": \"CVE-2026-2786\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-05-10T12:54:19.009Z\", \"dateReserved\": \"2026-02-19T15:06:24.424Z\", \"assignerOrgId\": \"f16b083a-5664-49f3-a51e-8d479e5ed7fe\", \"datePublished\": \"2026-02-24T13:33:18.980Z\", \"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.