CVE-2026-10949: Chrome Heap Overflow Sandbox Escape Vulnerability

Technical summary

CVE-2026-10949 is a heap buffer overflow (CWE-122) in Chrome's video processing subsystem. The vulnerability allows an attacker with renderer process control to write beyond allocated heap memory boundaries, corrupting adjacent memory structures. By crafting specific HTML video content, an attacker can leverage this overflow to break out of Chrome's sandbox isolation and execute arbitrary code with the privileges of the browser process. The high CVSS score (8.3) reflects the combination of system-level impact (confidentiality, integrity, availability all compromised) and cross-boundary scope breach, though the attack chain requires prior renderer compromise.

Business impact

This vulnerability poses significant risk to organizations where browser compromise is a realistic threat vector—particularly in environments targeted by advanced persistent threats (APTs), supply chain attacks, or malware distribution networks. A successful sandbox escape allows attackers to move from browser context to system kernel, potentially installing rootkits, stealing credentials, or pivoting to network resources. Organizations relying on browser sandboxing as a containment strategy for untrusted content should prioritize this patch. The requirement for initial renderer compromise means this is primarily a concern for high-value targets or environments with existing malware presence.

Affected systems

Google Chrome versions prior to 149.0.7827.53 are affected across all major operating systems: Windows, macOS, and Linux. The vulnerability is specific to Chrome's video processing engine and does not appear to affect Chrome derivatives differently based on the base vulnerability mechanism, though system-specific sandbox escape techniques may vary by OS. Organizations running older Chrome releases or those with auto-update disabled should inventory their deployment for pre-149.0.7827.53 versions.

Exploitability

While the vulnerability itself is technically exploitable, real-world exploitation requires a multi-stage attack: first compromising the Chrome renderer process (via malicious content, malware, or other vector), then triggering the heap overflow via crafted video HTML. The attack is not currently tracked in the CISA KEV catalog, indicating either limited observed exploitation or that practical weaponization remains limited. The requirement for prior renderer compromise and the need to craft specific video payloads places this in the 'post-compromise' category rather than 'remote unauthenticated.' However, organizations should not interpret this as low risk—advanced attackers frequently chain exploits, and sandbox escapes are valuable components in persistent threat toolkits.

Remediation

Update Google Chrome to version 149.0.7827.53 or later. This patch fixes the heap buffer overflow in the video component. Chrome typically auto-updates on most systems, but users should verify their version (Settings > About > Google Chrome) and manually trigger an update if needed. Organizations with managed Chrome deployments should push the patch through their update mechanism and verify compliance. No workarounds exist that eliminate the vulnerability; patching is the only remediation.

Patch guidance

Deploy Chrome 149.0.7827.53 or newer across all user devices and servers running Chrome. For enterprise deployments, verify the patch version through Chrome's version indicator or policy management console. If auto-update is disabled in your environment, manually distribute the update or re-enable automatic updates. Test the patch in a small cohort if your organization maintains strict change control, but prioritize deployment given the sandbox escape severity. Verify patch application within 30 days of availability, particularly for high-risk user segments (developers, researchers, high-value targets).

Detection guidance

Monitor for Chrome processes with abnormal memory access patterns or syscall sequences that suggest sandbox escape attempts. EDR solutions should flag suspicious privilege escalation following Chrome activity. Log Chrome version information to identify unpatched installations. Watch for heap corruption signals in crash dumps if Chrome processes terminate unexpectedly. On Windows, monitor for unusual kernel-mode code execution shortly after Chrome execution. On macOS and Linux, observe for unexpected child process spawning from Chrome with elevated privileges. Note that detection of actual in-the-wild exploitation will be challenging without telemetry from the renderer process itself.

Why prioritize this

Despite not yet appearing in CISA's KEV catalog, this vulnerability merits high priority due to its sandbox escape nature and high CVSS score. Sandbox breaks are force multipliers for attackers; once achieved, system compromise typically follows. Organizations should treat this as critical for high-risk user populations (developers, researchers, executives) and important for general deployment. The requirement for prior renderer compromise means this is not a direct remote threat, but when combined with other malware vectors or supply chain compromises, it becomes a critical escalation path. Prioritize users in environments where malware presence is historically higher or where multi-stage attacks are plausible.

Risk score, explained

The CVSS 8.3 HIGH score reflects multiple aggravating factors: the vulnerability requires user interaction (viewing a malicious HTML page, raising AC:H), but achieves complete confidentiality, integrity, and availability compromise once the renderer is compromised (C:H/I:H/A:H). Scope changes from isolated (renderer) to changed (system), as the escape breaks sandbox boundaries. Network attack vector (AV:N) applies because the malicious content can be served remotely. The score appropriately weights the severity of sandbox escape despite the prerequisite of renderer compromise. This is not a direct remote code execution; it's a privilege escalation within the browser ecosystem that leads to system compromise.

Frequently asked questions