High severity · published May 19, 2026
CVE-2026-8975
Memory safety bugs fixed in Thunderbird 140.11 and Thunderbird 151
8.8
CVSS
0.5%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
Required
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.5% · higher than 41% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
FI
Firefox · Mozilla
before 115.36.0; before 151.0.0; 140.0 before 140.11.0 · source: NVD
TH
Thunderbird · Mozilla
before 140.11; before 151.0.0 · source: NVD
RH
Red Hat Enterprise Linux 10 · Red Hat
All versions, or not specified · source: CISA
RH
Red Hat Enterprise Linux 10.0 Extended Update Support · Red Hat
All versions, or not specified · source: CISA
RH
Red Hat Enterprise Linux 6 · Red Hat
All versions, or not specified · source: CISA
RH
Red Hat Enterprise Linux 7 · Red Hat
All versions, or not specified · source: CISA
RH
Red Hat Enterprise Linux 7 Extended Lifecycle Support · Red Hat
All versions, or not specified · source: CISA
RH
Red Hat Enterprise Linux 8 · Red Hat
All versions, or not specified · source: CISA
RH
Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support · Red Hat
All versions, or not specified · source: CISA
RH
Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On · Red Hat
All versions, or not specified · source: CISA
RH
Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support · Red Hat
All versions, or not specified · source: CISA
RH
Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On · Red Hat
All versions, or not specified · source: CISA
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-8975
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-8975
Permissions Required
https://bugzilla.mozilla.org/buglist.cgi?bug_id=1860195%2C2029325%2C2029429%2C2029910%2C2035915%2C2038678%2C2038669
Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-46/
Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-47/
Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-48/
Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-50/
Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-51/
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