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Internally found bugs fixed in Firefox ESR 115.39, Firefox ESR 140.14, Firefox ESR 153.1 and Firefox 154

Type: advisorySources: Official CVE List

Internally found bugs present in Firefox ESR 115.38, 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 115.39, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.

Products
Firefox, Thunderbird
Affected versions
Not specified
Fixed versions
Not specified
CVEs
CVE-2026-74990
Confirmed fixed CVEs
Not specified
Updated in this feed
1 Nov 2026, 17:45 UTC · Revision 1

Source evidence

Internally found bugs fixed in Firefox ESR 115.39, Firefox ESR 140.14, Firefox ESR 153.1 and Firefox 154

core-cve · Original source

Published 18 Aug 2026, 12:23 UTC

Internally found bugs present in Firefox ESR 115.38, 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 115.39, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.

cve:CVE-2026-74990

Firefox

Fixed versions: Not specified

Thunderbird

Fixed versions: Not specified

Complete source record
{
  "id": "ddb67ab7de2d3126693a178d4b1481a0ebd96557afcf738d55ab7f22e857c2f5",
  "url": "https://www.cve.org/CVERecord?id=CVE-2026-74990",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Internally found bugs fixed in Firefox ESR 115.39, Firefox ESR 140.14, Firefox ESR 153.1 and Firefox 154",
    "summary": "Internally found bugs present in Firefox ESR 115.38, 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 115.39, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.",
    "evidence": "cve:CVE-2026-74990",
    "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-2026-74990",
      "aliases": [
        "CVE-2026-74990"
      ],
      "metrics": [],
      "affected": [
        {
          "vendor": "Mozilla",
          "product": "Firefox",
          "versions": [
            {
              "status": "unaffected",
              "version": "115.39",
              "versionType": "rpm",
              "lessThanOrEqual": "115.*"
            },
            {
              "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": "2026-10-28T16:35:53.190Z",
      "provider": "cve",
      "references": [
        "https://bugzilla.mozilla.org/buglist.cgi?bug_id=2045762%2C2052401%2C2058208",
        "https://bugzilla.mozilla.org/buglist.cgi?bug_id=2045774%2C2048490%2C2050864%2C2053159%2C2053260%2C2053261%2C2053582%2C2053599%2C2053607%2C2053608%2C2053853%2C2054626%2C2054627%2C2054635%2C2054677%2C2054740%2C2054832%2C2056792%2C2057098%2C2057100%2C2057101%2C2057103%2C2057117%2C2057118%2C2058048%2C2058049%2C2058622%2C2058623%2C2058665%2C2058666%2C2059121%2C2059164%2C2059188",
        "https://www.mozilla.org/security/advisories/mfsa2026-74/",
        "https://www.mozilla.org/security/advisories/mfsa2026-75/",
        "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-2026-74990",
                    "role": "CISA Coordinator",
                    "options": [
                      {
                        "Exploitation": "none"
                      },
                      {
                        "Automatable": "yes"
                      },
                      {
                        "Technical Impact": "total"
                      }
                    ],
                    "version": "2.0.3",
                    "timestamp": "2026-08-18T19:27:52.706061Z"
                  }
                }
              }
            ],
            "problemTypes": [
              {
                "descriptions": [
                  {
                    "lang": "en",
                    "type": "CWE",
                    "cweId": "CWE-119",
                    "description": "CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer"
                  }
                ]
              }
            ],
            "providerMetadata": {
              "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "shortName": "CISA-ADP",
              "dateUpdated": "2026-08-18T19:28:52.918Z"
            }
          }
        ],
        "cna": {
          "orgId": "f16b083a-5664-49f3-a51e-8d479e5ed7fe",
          "shortName": "mozilla",
          "dateUpdated": "2026-10-28T16:35:53.190Z"
        }
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-74990",
        "evidence": "/cveMetadata/cveId"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-cve",
  "document_id": 461094,
  "published_at": "2026-08-18T12:23:35.129+00:00"
}