CVE-2025-1020

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{"bugzilla": {"description": "firefox: thunderbird: Memory safety bugs fixed in Firefox 135 and Thunderbird 135", "id": "2343757", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2343757"}, "csaw": false, "cvss3": {"cvss3_base_score": "8.8", "cvss3_scoring_vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H", "status": "draft"}, "cwe": "CWE-120", "details": ["Memory safety bugs present in Firefox 134 and Thunderbird 134. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 135 and Thunderbird < 135.", "A flaw was found in Firefox. The Mozilla Foundation's Security Advisory describes the following issue: Memory safety bugs present in Firefox 134 and Thunderbird 134. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code."], "name": "CVE-2025-1020", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Fix deferred", "package_name": "firefox", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Fix deferred", "package_name": "firefox-flatpak-container", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Fix deferred", "package_name": "thunderbird", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Fix deferred", "package_name": "thunderbird-flatpak-container", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Fix deferred", "package_name": "firefox", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Fix deferred", "package_name": "thunderbird", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Fix deferred", "package_name": "firefox", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Fix deferred", "package_name": "thunderbird", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Fix deferred", "package_name": "firefox", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Fix deferred", "package_name": "thunderbird", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Fix deferred", "package_name": "firefox", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Fix deferred", "package_name": "firefox-flatpak-container", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Fix deferred", "package_name": "thunderbird", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Fix deferred", "package_name": "thunderbird-flatpak-container", "product_name": "Red Hat Enterprise Linux 9"}], "public_date": "2025-02-04T13:58:56Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2025-1020\nhttps://nvd.nist.gov/vuln/detail/CVE-2025-1020\nhttps://bugzilla.mozilla.org/buglist.cgi?bug_id=1939063%2C1942169\nhttps://www.mozilla.org/security/advisories/mfsa2025-07/\nhttps://www.mozilla.org/security/advisories/mfsa2025-11/"], "statement": "Red Hat Product Security rates the severity of this flaw as determined by the Mozilla Foundation Security Advisory", "threat_severity": "Important"}

{"analysis": {"en": {"generated_at": "2026-04-20T23:52:03.490315+00:00", "value": {"mitigation_remediation": ["Apply the latest Mozilla Firefox release (135 or newer) or a patch that brings the client up to the fixed version.", "Apply the corresponding Thunderbird update to version 135 or later to eliminate the bug.", "If an immediate update is infeasible, restrict network access to vulnerable clients and monitor for signs of exploitation; evaluate disabling risky extensions or features that might trigger the memory corruption path."], "summary": {"action": "Immediate Patch", "impact": "Remote Code Execution"}, "threat_synthesis": {"affected_systems": "Mozilla Firefox 134 and Mozilla Thunderbird 134 are affected. The fixes were released in Firefox 135 and Thunderbird 135 respectively.", "description_and_impact": "These memory safety bugs were discovered in Firefox 134 and Thunderbird 134 and involve buffer copy or out\u2011of\u2011bounds write vulnerabilities that can corrupt memory. In theory, with sufficient effort an attacker could exploit the corruption to execute arbitrary code on the victim\u2019s system. The weakness is reflected in CWE\u2011120 and CWE\u2011787, indicating unsafe handling of memory boundaries.", "risk_and_exploitability": "The CVSS score of 9.8 points to a severe risk, but the EPSS score of < 1% suggests that exploitation is unlikely at present. The vulnerability is not listed in the CISA KEV catalog, indicating no confirmed widespread attacks. Nevertheless, the potential for remote code execution makes this a critical upgrade target, especially in environments where vulnerable versions may remain installed."}}}}, "created": "2026-04-21T00:00:13.384306+00:00", "updated": "2026-04-21T00:00:13.384329+00:00", "vendors": []}