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Mallory
Critical

Sandbox escape in Headless mode in Google Chrome

IdentifiersCVE-2026-12027CWE-693· Protection Mechanism Failure

CVE-2026-12027 is a high-severity vulnerability in the Headless component of Google Chrome caused by inappropriate implementation / insufficient policy enforcement. In Google Chrome prior to 149.0.7827.115, a remote attacker who had already compromised the renderer process could potentially escape the browser sandbox via a crafted HTML page. The issue affects Chrome's Headless mode and represents a failure to correctly enforce security boundaries between a compromised renderer and the sandboxed execution environment.

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For your environment

Are you exposed to this one?

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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 an attacker who already achieved renderer-process compromise to break out of the Chrome sandbox. This would significantly increase the impact of the initial compromise by enabling code execution or actions outside the renderer's sandbox restrictions, with consequent risk of broader system compromise. Vendor and downstream advisories also note that Chromium vulnerabilities in this release set may lead to arbitrary code execution, denial of service, or information disclosure, but for this specific CVE the primary documented impact is sandbox escape.

Mitigation

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

No specific workaround or temporary mitigation was provided in the available advisories. The practical mitigation is to reduce exposure by disabling or avoiding vulnerable Headless Chrome deployments where feasible and to apply the patched browser/package versions as soon as possible.

Remediation

Patch, then assume compromise.

Upgrade Google Chrome to version 149.0.7827.115 or later. For Debian-based Chromium deployments, apply the vendor security update and upgrade chromium to 149.0.7827.114-1~deb12u1 on Debian oldstable (bookworm) or 149.0.7827.114-1~deb13u1 on Debian stable (trixie), as provided by the Debian advisory.
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
GoogleChromeapplication

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

ACTIVITY FEED

Recent activity

4 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.

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 activity2

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