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Mallory
High

Use-after-free RCE in Google Chrome Prerender

IdentifiersCVE-2026-6299CWE-416· Use After Free

CVE-2026-6299 is a critical use-after-free vulnerability in Google Chrome's Prerender component affecting versions prior to 147.0.7727.101. The flaw is a lifetime-management bug in the prerender cancellation path: when a prerendered new-tab WebContents is canceled, synchronous destruction of the associated PrerenderNewTabHandle/WebContents can occur while BrowsingDataRemoverImpl is iterating over a snapshot of live WebContents raw pointers. This leaves a dangling pointer that can later be dereferenced, creating a use-after-free condition. The vulnerable path can be triggered during prerender cancellation, including via BrowsingDataRemoverImpl::RemoveImpl, and the provided context specifically notes that a Clear-Site-Data HTTP header can trigger that removal flow. Because Chrome prerenders pages in a hidden background tab, attacker-controlled content may begin executing before the user explicitly clicks the destination. Successful exploitation allows a remote attacker to achieve arbitrary code execution via a crafted HTML page.

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ANALYST BRIEF

Impact, mitigation & remediation

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Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation can result in arbitrary code execution in the context of the target Chrome process through memory corruption in the Prerender subsystem. The CVSS context provided indicates high impact to confidentiality, integrity, and availability. Because prerendered content can execute in the background before explicit navigation, the flaw increases practical exploitability compared with bugs that require a full user click-through before attacker-controlled code runs. Depending on exploit reliability and post-exploitation chaining, this can provide a foothold for further compromise of the browser session and potentially broader system impact.

Mitigation

If you can’t patch tonight, do this now.

No vendor workaround is confirmed in the provided content. If immediate patching is not possible, reducing exposure to prerender-triggered navigation paths may lower risk, but the content does not provide an official mitigation. The only confirmed mitigation/remediation in the available information is to apply the patched browser version.

Remediation

Patch, then assume compromise.

Update Google Chrome to version 147.0.7727.101 or later; the fix shipped in Chrome 147.0.7727.101/.102 on April 15, 2026. Chromium-based browsers that incorporate the affected Prerender code should be updated to builds that include the upstream Chromium fix for bug 497053588. The patch changes the cancellation/destruction model by replacing the instance cancellation method with a static ownership-transferring cancellation routine and deferring destruction with DeleteSoon() to avoid synchronous teardown during active iteration.
PUBLIC EXPLOITS

Exploits

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VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

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VendorProductType
GoogleChromeapplication

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Threat actor evidence

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Associated malware

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Detection signatures

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Social activity4

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