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Mallory
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Use-after-free in WebShare in Google Chrome on Windows

IdentifiersCVE-2026-12437CWE-416

CVE-2026-12437 is a critical use-after-free vulnerability in the WebShare component of Google Chrome on Windows prior to version 149.0.7827.155. The flaw is a memory-safety error in which an object in WebShare can be accessed after it has been freed, creating a condition for memory corruption. According to the provided advisory context, exploitation is possible via a crafted HTML page, but requires that the attacker has already compromised the renderer process. In that post-renderer-compromise state, the bug can be used to cross Chrome's security boundary and potentially escape the sandbox. The issue is also inherited by Chromium-based browsers that consumed the vulnerable upstream Chromium code, including Microsoft Edge until the corresponding fixed release.

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For your environment

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

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

Successful exploitation could allow a remote attacker who has already achieved renderer-process compromise to leverage the WebShare use-after-free for memory corruption and a potential browser sandbox escape on affected Windows systems. In practical terms, this can let an attacker break out of the renderer's restricted execution context and gain code execution or broader control in a more privileged browser process context, materially increasing the impact of an initial browser compromise.

Mitigation

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

No specific workaround is provided in the supplied advisories beyond upgrading to a fixed version. As interim risk reduction, organizations can prioritize rapid browser patching, reduce exposure to untrusted web content, and apply defense-in-depth controls such as browser isolation and endpoint protections, but these measures are not substitutes for the vendor fix.

Remediation

Patch, then assume compromise.

Upgrade Google Chrome on Windows to version 149.0.7827.155 or later. For Chromium downstreams, apply the vendor-provided fixed builds; for example, Microsoft Edge should be updated to version 149.0.4022.80 or later, and Debian chromium should be updated to 149.0.7827.155-1~deb13u1 on trixie or 149.0.7827.155-1~deb12u1 on bookworm, as applicable.
PUBLIC EXPLOITS

Exploits

No public exploits tracked yet. Mallory keeps watching.

VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType
DebianChromiumapplication
GoogleChromeapplication

Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.

What this page doesn’t show

The version that knows your environment.

This page is what’s public. Mallory adds the parts that aren’t: which of your assets are affected, which adversaries are exploiting it right now, which detections to deploy, and what to do tonight.
Exposure mapping

Query your assets running an affected version, and investigate the blast radius.

Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware

Malware families riding this exploit, with evidence and IOCs.

Detection signatures

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity1

Community discussion across Reddit, Mastodon, and other social sources.