Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain
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AccessLure victim to crafted web page
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DeliveryDeliver malicious HTML to renderer
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ExploitTrigger use-after-free in Geometry
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ExecutionReclaim freed object, hijack control flow
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ImpactExecute arbitrary code inside sandbox
Vulnerability Assessment
| Weakness |
CWE
ASVS 5.0
V15 - Secure Coding and Architecture Memory lifecycle management
MITRE ATT&CK
2 techniques across 2 tactics: Execution, Privilege Escalation The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Exploitation Conditions | Exploitation requires a victim using Google Chrome prior to 157.0.8103.38 to load attacker-controlled content - a crafted HTML page that exercises the vulnerable Geometry code path (UI:R). No authentication or prior privileges are needed (PR:N), and no non-default configuration is required; any default Chrome install below the fixed version is affected. Key limiting factors: (1) the attack requires user interaction - the victim must navigate to or render the malicious page; (2) resulting code execution is confined to the renderer sandbox (S:U, and the description states 'inside the sandbox'), so a separate sandbox-escape chain would be needed to compromise the host. Updating to 157.0.8103.38 or later is the fix provided by the vendor. |
| Impact | This is a genuine high-priority patching item, though not a drop-everything emergency on current signals. The supplied CVSS 3.1 vector (AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H, 8.8) indicates a network-reachable, low-complexity, unauthenticated flaw that requires user interaction (visiting a crafted page) and does NOT cross the sandbox boundary (S:U) - the description explicitly confirms code execution is 'inside the sandbox,' so this alone is not a full browser escape. Chromium rates the underlying severity Critical, reflecting the reliability/impact of the use-after-free, while the numeric CVSS is High because of the UI:R requirement and unchanged scope. No EPSS score was provided, so exploitation probability cannot be quantified. No KEV listing and no public exploit are present in the input, so this is 'no public exploit identified at time of analysis' - distinct from active exploitation. The vuln.today decision label is 'this_week,' consistent with a patched, high-severity browser memory-corruption bug that is realistic to weaponize but not yet observed in the wild. SSVC-style read: exploitation=none/public-none, automatable=no (requires a victim to load a page), technical impact=total within the renderer sandbox. Net: treat as a within-the-week priority - patch promptly, but the sandbox confinement and the need for user interaction temper it below an act_now/emergency classification. |
| Exploit ScenarioDerived | An attacker hosts or injects a malicious HTML page that triggers the use-after-free in Chrome's Geometry component when rendered; a victim is lured to visit it (e.g., via link, ad, or compromised site). Successful exploitation yields arbitrary code execution within the renderer sandbox. No public exploit code is identified in the provided data, and the low attack complexity (AC:L) means a reliable trigger is plausible once the bug is understood, but user interaction (UI:R) is required. |
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Alert meAnalysisAIv1 – Nov 03, 2026
Use-after-free in Google Chrome's Geometry component before 157.0.8103.38 lets a remote attacker who convinces a victim to load a crafted HTML page execute arbitrary code inside the renderer sandbox. The issue is rated CVSS 8.8 with UI:R and PR:N, so default Chrome installations below the fixed version are exposed when the victim renders attacker-controlled content; no public exploit was identified at the time of analysis, and code execution from this flaw alone remains confined to the sandbox unless chained with a separate escape.
RemediationAI
Vendor-released patch: Google Chrome 157.0.8103.38. Update affected installations to 157.0.8103.38 or later using the Chrome stable-channel release; the advisory is at https://chromereleases.googleblog.com/2026/11/stable-channel-update-for-desktop.html and the Chromium issue is https://issues.chromium.org/issues/571065824. The available sources do not describe a separate workaround, and the vendor fix is the version update; until it is applied, exposure is limited to users who render crafted HTML content, and code execution from this bug alone remains inside the renderer sandbox.
Affected VersionsENISA
Affected Packages
Source: OSV (Open Source Vulnerabilities)
Affects your stack
Affects 1 package in euvd
Checking this CVE against your own stacks and servers is part of the Basic plan and up.
Technical ContextAI · show details
CVE-2026-121203 is a CWE-416 use-after-free in the Geometry component of Google Chrome/Chromium. A use-after-free occurs when an object is freed and later dereferenced; in a browser renderer this class of memory-corruption bug can allow arbitrary code execution when malicious content causes the stale reference to be used. The CVSS vector AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H describes a network-delivered attack that requires the victim to interact with a crafted HTML page and requires no privileges, while the description and assessment confine the resulting code execution to the renderer sandbox, meaning host compromise would require an additional sandbox-escape chain. The available sources identify the affected CPE as cpe:2.3:a:google:chrome:*:*:*:*:*:*:*:* and do not describe the precise Geometry trigger beyond the crafted HTML page.
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- Exploit and PoC references, threat intelligence from 22 sources
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Severity by source
AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Remote crafted page with no privileges (AV:N/PR:N) but victim must load it (UI:R); use-after-free gives reliable code execution confined to the sandbox (S:U), yielding high C/I/A.
Primary rating from Vendor (Chrome).
CVSS VectorVendor: Chrome
Lifecycle Timeline
3DescriptionCVE.org
Use after free in Geometry in Google Chrome prior to 157.0.8103.38 allowed a remote attacker to execute arbitrary code inside the sandbox via a crafted HTML page. (Chromium security severity: Critical)
Executive ViewAI
A high-severity vulnerability in Google Chrome's Geometry component (CVE-2026-121203) allows remote attackers to execute arbitrary code within the browser's sandbox when users visit a crafted webpage. With Chrome widely deployed across the organization, this flaw poses a significant risk to endpoint integrity and sensitive data, though no public exploit has been identified. Leadership should prioritize patching to the latest version to prevent potential exploitation and maintain security posture.
Apply vendor patch.
Threat Intelligence Overview
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
Use-after-free vulnerabilities occur when a program continues to access memory through a pointer after that memory has been deallocated.
Memory corruption occurs when a program writes data beyond the boundaries of allocated memory regions or accesses memory in unintended ways, violating the integrity of the process's address space.
Remote Code Execution represents the critical moment when an attacker successfully runs arbitrary code on a target system without physical access.
Denial of Service attacks render applications or systems unavailable by overwhelming resources or triggering failure conditions.
EUVD-2026-116503
GHSA-436r-f3j8-ph5v
NVD
CVE.org
Vulnrichment
Exploit-DB