CVE-2026-8975

Memory safety bugs fixed in Thunderbird 140.11 and Thunderbird 151

Published May 19, 2026 CVSS 3.1 · 8.8 High EPSS < 1% KEV · Not listed
Description
Memory safety bugs present in Thunderbird 140.10 and Thunderbird 150. 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 was fixed in Firefox 151, Firefox ESR 115.36, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Debian DLA Debian DLA DLA-4592-1 firefox-esr security update
Debian DLA Debian DLA DLA-4594-1 thunderbird security update
Debian DSA Debian DSA DSA-6283-1 firefox-esr security update
Debian DSA Debian DSA DSA-6288-1 thunderbird security update
References
Link Providers
https://access.redhat.com/errata/RHSA-2026:21378 cve-icon
https://access.redhat.com/errata/RHSA-2026:21380 cve-icon
https://access.redhat.com/errata/RHSA-2026:21381 cve-icon
https://access.redhat.com/errata/RHSA-2026:21382 cve-icon
https://access.redhat.com/errata/RHSA-2026:22325 cve-icon
https://access.redhat.com/errata/RHSA-2026:22643 cve-icon
https://access.redhat.com/errata/RHSA-2026:26174 cve-icon
https://access.redhat.com/errata/RHSA-2026:26268 cve-icon
https://access.redhat.com/errata/RHSA-2026:26269 cve-icon
https://access.redhat.com/errata/RHSA-2026:26270 cve-icon
https://access.redhat.com/errata/RHSA-2026:26491 cve-icon
https://access.redhat.com/errata/RHSA-2026:26492 cve-icon
https://access.redhat.com/errata/RHSA-2026:26493 cve-icon
https://access.redhat.com/errata/RHSA-2026:26521 cve-icon
https://access.redhat.com/errata/RHSA-2026:26536 cve-icon
https://access.redhat.com/errata/RHSA-2026:26539 cve-icon
https://access.redhat.com/errata/RHSA-2026:26551 cve-icon
https://access.redhat.com/errata/RHSA-2026:26606 cve-icon
https://access.redhat.com/errata/RHSA-2026:26629 cve-icon
https://access.redhat.com/errata/RHSA-2026:26630 cve-icon
https://access.redhat.com/errata/RHSA-2026:27715 cve-icon
https://access.redhat.com/security/cve/CVE-2026-8975 cve-icon
https://bugzilla.mozilla.org/buglist.cgi?bug_id=1860195%2C2029325%2C2029429%2C2029910%2C2035915%2C2038678%2C2038669 cve-icon cve-icon
https://bugzilla.redhat.com/show_bug.cgi?id=2479840 cve-icon
https://nvd.nist.gov/vuln/detail/CVE-2026-8975 cve-icon
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-8975.json cve-icon
https://www.cve.org/CVERecord?id=CVE-2026-8975 cve-icon
https://www.mozilla.org/security/advisories/mfsa2026-46/ cve-icon cve-icon
https://www.mozilla.org/security/advisories/mfsa2026-47/ cve-icon cve-icon
https://www.mozilla.org/security/advisories/mfsa2026-48/ cve-icon cve-icon
https://www.mozilla.org/security/advisories/mfsa2026-48/#CVE-2026-8975 cve-icon
https://www.mozilla.org/security/advisories/mfsa2026-50/ cve-icon cve-icon
https://www.mozilla.org/security/advisories/mfsa2026-51/ cve-icon cve-icon
History
Type Values Removed Values Added
Description Memory safety bugs present in Firefox ESR 115.35, Firefox ESR 140.10 and Firefox 150. 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 was fixed in Firefox 151, Firefox ESR 115.36, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11. Memory safety bugs present in Thunderbird 140.10 and Thunderbird 150. 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 was fixed in Firefox 151, Firefox ESR 115.36, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.
Title Memory safety bugs fixed in Firefox ESR 115.36, Firefox ESR 140.11 and Firefox 151 Memory safety bugs fixed in Thunderbird 140.11 and Thunderbird 151
Type Values Removed Values Added
Description Memory safety bugs present in Thunderbird 140.10 and Thunderbird 150. 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 was fixed in Firefox 151, Firefox ESR 115.36, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11. Memory safety bugs present in Firefox ESR 115.35, Firefox ESR 140.10 and Firefox 150. 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 was fixed in Firefox 151, Firefox ESR 115.36, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.
Title Memory safety bugs fixed in Thunderbird 140.11 and Thunderbird 151 Memory safety bugs fixed in Firefox ESR 115.36, Firefox ESR 140.11 and Firefox 151
Type Values Removed Values Added
Metrics cvssV3_1

{'score': 9.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'}

ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

cvssV3_1

{'score': 8.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H'}

ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Mozilla thunderbird
CPEs cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:*
cpe:2.3:a:mozilla:firefox:*:*:*:*:esr:*:*:*
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:-:*:*:*
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:esr:*:*:*
Vendors & Products Mozilla thunderbird
Type Values Removed Values Added
Weaknesses CWE-120
CWE-122
Type Values Removed Values Added
Description Memory safety bugs present in Firefox ESR 115.35, Firefox ESR 140.10 and Firefox 150. 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 was fixed in Firefox 151, Firefox ESR 115.36, and Firefox ESR 140.11. Memory safety bugs present in Thunderbird 140.10 and Thunderbird 150. 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 was fixed in Firefox 151, Firefox ESR 115.36, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.
Title Memory safety bugs fixed in Firefox ESR 115.36, Firefox ESR 140.11 and Firefox 151 Memory safety bugs fixed in Thunderbird 140.11 and Thunderbird 151
References
Type Values Removed Values Added
Weaknesses CWE-119
Metrics cvssV3_1

{'score': 9.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'}

ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
Weaknesses CWE-120
CWE-122
Type Values Removed Values Added
First Time appeared Mozilla
Mozilla firefox
Vendors & Products Mozilla
Mozilla firefox
Type Values Removed Values Added
Description Memory safety bugs present in Firefox ESR 115.35, Firefox ESR 140.10 and Firefox 150. 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 was fixed in Firefox 151, Firefox ESR 115.36, and Firefox ESR 140.11.
Title Memory safety bugs fixed in Firefox ESR 115.36, Firefox ESR 140.11 and Firefox 151
References
Weaknesses

Sources

Status
PUBLISHED
Assigner
mozilla
Published
Updated
Oct 21, 2026, 1:50 PM
Reserved
May 19, 2026, 12:30 PM
Status
Modified
Published
May 19, 2026, 2:16 PM
Modified
Oct 21, 2026, 2:17 PM
Severity
Important
Public date
May 19, 2026, 12:30 PM