{"id":"CVE-2026-12291","title":"Use-after-free in the Networking: HTTP component","summary":"Use-after-free in the Networking: HTTP component. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Firefox ESR 115.37, Thunderbird 152, and Thunderbird 140.12.","severity":"high","cvss":8.8,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H","cwe":["CWE-416","CWE-825"],"vendor":"mozilla","product":"firefox","affected":["firefox < 115.37.0","firefox < 152.0.0","firefox >= 128.0, < 140.12.0","thunderbird < 140.12.0","thunderbird < 152.0.0"],"patched":["firefox 140.12.0","thunderbird 152.0.0"],"published":"2026-06-16","updated":"2026-07-07","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-12291","references":[{"url":"https://bugzilla.mozilla.org/show_bug.cgi?id=2036929","label":"security@mozilla.org"},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-57/","label":"security@mozilla.org"},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-58/","label":"security@mozilla.org"},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-59/","label":"security@mozilla.org"},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-60/","label":"security@mozilla.org"},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-61/","label":"security@mozilla.org"},{"url":"https://access.redhat.com/errata/RHSA-2026:27717","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/errata/RHSA-2026:27733","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/errata/RHSA-2026:27734","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/errata/RHSA-2026:29940","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/errata/RHSA-2026:30846","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/errata/RHSA-2026:33445","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/errata/RHSA-2026:36100","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/errata/RHSA-2026:36101","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/errata/RHSA-2026:36102","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/errata/RHSA-2026:36103","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/security/cve/CVE-2026-12291","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2489244","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-12291.json","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"}],"tags":["nvd"],"epss":0.00382,"epssPercentile":0.32079,"ingestedAt":"2026-07-07T12:52:59.649Z","slug":"CVE-2026-12291","body":"## Overview\n\nUse-after-free in the Networking: HTTP component. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Firefox ESR 115.37, Thunderbird 152, and Thunderbird 140.12.\n\n## Affected\n\n- `firefox < 115.37.0`\n- `firefox < 152.0.0`\n- `firefox >= 128.0, < 140.12.0`\n- `thunderbird < 140.12.0`\n- `thunderbird < 152.0.0`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `firefox 140.12.0`\n- `thunderbird 152.0.0`","depth":"twilight","depthScore":48,"depthScoreParts":{"impact":48.4,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}