CVE-2026-16411: Memory safety bugs fixed in Thunderbird 153

Severity: critical (CVSS 9.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.6% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-07-21 · updated 2026-10-21
Weakness: CWE-119

Description

Memory safety bugs present in Thunderbird 152. 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 153 and Thunderbird 153.

Affected products

Mozilla Firefox: before 153.0.0 — fixed in 153.0.0

How to fix

Upgrade to a fixed version: Mozilla Firefox 153.0.0. Check the vendor advisory for mitigations.

References

https://bugzilla.mozilla.org/buglist.cgi?bug_id=1420800%2C1598946%2C1767921%2C2013993%2C2025417%2C2027325%2C2027364%2C2029433%2C2029807%2C2029901%2C2029922%2C2030102%2C2030563%2C2032110%2C2037801%2C2042756%2C2044625%2C2045609%2C2047920%2C2048491%2C2048492%2C2048800%2C2050534%2C2050662%2C2050871
https://bugzilla.mozilla.org/buglist.cgi?bug_id=2006467%2C2027346%2C2027349%2C2027353%2C2027362%2C2027371%2C2027373%2C2028954%2C2029694%2C2036906%2C2038964%2C2039460%2C2040522%2C2040834%2C2043275%2C2045394%2C2045606%2C2052060
https://bugzilla.mozilla.org/buglist.cgi?bug_id=2048936%2C2049804
https://www.mozilla.org/security/advisories/mfsa2026-68/
https://www.mozilla.org/security/advisories/mfsa2026-71/

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