Internally found bugs fixed in Firefox ESR 140.14, Firefox ESR 153.1 and Firefox 154

{
  "id": "c0bec336ccc945d70b3bf94734c95cc25376a378c7f1891f1803b72c605a7b90",
  "url": "https://www.cve.org/CVERecord?id=CVE-2026-74987",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Internally found bugs fixed in Firefox ESR 140.14, Firefox ESR 153.1 and Firefox 154",
    "summary": "Internally found bugs present in Firefox ESR 140.13, Firefox ESR 153.0 and Firefox 153. Some of these bugs showed evidence of memory corruption or another security-relevant defect and we presume that with enough effort some of these could have been exploited. This vulnerability was fixed in Firefox 154, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.",
    "evidence": "cve:CVE-2026-74987",
    "products": [
      {
        "name": {
          "value": "Firefox",
          "evidence": "/containers/cna/affected/0/product"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": []
      },
      {
        "name": {
          "value": "Thunderbird",
          "evidence": "/containers/cna/affected/1/product"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2026-74987",
      "aliases": [
        "CVE-2026-74987"
      ],
      "metrics": [],
      "affected": [
        {
          "vendor": "Mozilla",
          "product": "Firefox",
          "versions": [
            {
              "status": "unaffected",
              "version": "140.14",
              "versionType": "rpm",
              "lessThanOrEqual": "140.*"
            },
            {
              "status": "unaffected",
              "version": "153.1",
              "versionType": "rpm",
              "lessThanOrEqual": "153.*"
            },
            {
              "status": "unaffected",
              "version": "154",
              "versionType": "rpm",
              "lessThanOrEqual": "*"
            }
          ]
        },
        {
          "vendor": "Mozilla",
          "product": "Thunderbird",
          "versions": [
            {
              "status": "unaffected",
              "version": "140.14",
              "versionType": "rpm",
              "lessThanOrEqual": "140.*"
            },
            {
              "status": "unaffected",
              "version": "153.1",
              "versionType": "rpm",
              "lessThanOrEqual": "153.*"
            },
            {
              "status": "unaffected",
              "version": "154",
              "versionType": "rpm",
              "lessThanOrEqual": "*"
            }
          ]
        }
      ],
      "modified": "2026-10-28T16:35:52.498Z",
      "provider": "cve",
      "references": [
        "https://bugzilla.mozilla.org/buglist.cgi?bug_id=1500946%2C1788109%2C2045379%2C2045380%2C2049339%2C2049393%2C2053580%2C2054662%2C2054665%2C2054673%2C2054785%2C2058645",
        "https://bugzilla.mozilla.org/buglist.cgi?bug_id=2048797%2C2050536%2C2053272%2C2053579%2C2057115%2C2057116%2C2057130%2C2057991%2C2057995%2C2058002%2C2058008%2C2058032%2C2058102%2C2058667",
        "https://bugzilla.mozilla.org/show_bug.cgi?id=2059424",
        "https://www.mozilla.org/security/advisories/mfsa2026-74/",
        "https://www.mozilla.org/security/advisories/mfsa2026-76/",
        "https://www.mozilla.org/security/advisories/mfsa2026-77/",
        "https://www.mozilla.org/security/advisories/mfsa2026-78/",
        "https://www.mozilla.org/security/advisories/mfsa2026-79/",
        "https://www.mozilla.org/security/advisories/mfsa2026-80/"
      ],
      "provider_metadata": {
        "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-2026-74987",
                    "role": "CISA Coordinator",
                    "options": [
                      {
                        "Exploitation": "none"
                      },
                      {
                        "Automatable": "yes"
                      },
                      {
                        "Technical Impact": "total"
                      }
                    ],
                    "version": "2.0.3",
                    "timestamp": "2026-08-19T13:05:41.543564Z"
                  }
                }
              }
            ],
            "problemTypes": [
              {
                "descriptions": [
                  {
                    "lang": "en",
                    "type": "CWE",
                    "cweId": "CWE-119",
                    "description": "CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer"
                  }
                ]
              }
            ],
            "providerMetadata": {
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              "shortName": "CISA-ADP",
              "dateUpdated": "2026-08-19T13:05:54.373Z"
            }
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        "cna": {
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          "shortName": "mozilla",
          "dateUpdated": "2026-10-28T16:35:52.498Z"
        }
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-74987",
        "evidence": "/cveMetadata/cveId"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-cve",
  "document_id": 461091,
  "published_at": "2026-08-18T12:23:34.847+00:00"
}