The IonMonkey just-in-time (JIT) compiler in Firefox before 66.0 can leak an internal JS_OPTIMIZED_OUT magic value to the running script during a bailout. This magic value can then be used by JavaScript to achieve memory corruption, which results in a potentially exploitable crash.
The IonMonkey just-in-time (JIT) compiler in Firefox before 66.0 can leak an internal JS_OPTIMIZED_OUT magic value to the running script during a bailout. This magic value can then be used by JavaScript to achieve memory corruption, which results in a potentially exploitable crash.
https://www.mozilla.org/en-US/security/advisories/mfsa2019-07/#CVE-2019-9792 https://bugzilla.mozilla.org/show_bug.cgi?id=1532599
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