CVE-2026-11246: Chrome IndexedDB Input Validation Vulnerability (5.3 MEDIUM)

Technical summary

The vulnerability exists in IndexedDB's input validation logic. IndexedDB is a NoSQL database API in modern browsers that allows websites to store structured data client-side. The insufficient validation of untrusted input allows a compromised renderer process to construct a crafted HTML page that violates the same-origin policy (SOP)—the fundamental browser security model that isolates data by origin. An attacker who has already compromised the renderer through another exploit or vulnerability can leverage this flaw to access or modify data that should be isolated to a different origin. The CVSS 3.1 vector (CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:N) reflects network attack surface, high attack complexity (due to the prerequisite renderer compromise), user interaction, and high integrity impact with no confidentiality or availability loss.

Business impact

For organizations, this vulnerability primarily affects data integrity rather than confidentiality or availability. If an attacker gains control of a user's renderer process through a separate vulnerability or social engineering, they could potentially modify or corrupt web application data stored via IndexedDB—such as cached credentials, local application state, or user-created content. This could lead to silent data corruption, unauthorized modifications visible to the user, or loss of trust in web-based applications. The impact is most significant for web applications that store sensitive user data locally and rely on the same-origin policy as a security boundary.

Affected systems

Google Chrome versions prior to 149.0.7827.53 on Windows, macOS, and Linux are directly affected. The vulnerability also affects the underlying operating systems (Windows, macOS, and Linux kernel) insofar as they host the vulnerable browser. Users of Chromium-based browsers that incorporate the vulnerable code may also be affected; verify the patch status of Edge, Brave, Opera, and other Chromium derivatives against their respective security advisories.

Exploitability

Exploitation requires a two-stage attack: first, the attacker must compromise the Chrome renderer process through an independent vulnerability or social engineering, and second, they must deliver a crafted HTML page to that compromised renderer. The CVSS assessment of "High" attack complexity reflects this dependency. The vulnerability is not in CISA's Known Exploited Vulnerabilities (KEV) catalog, indicating no evidence of active exploitation in the wild as of the publication date. However, the flaw is logically straightforward once renderer access is obtained, so defensive urgency should account for the broader renderer compromise landscape.

Remediation

Update Google Chrome to version 149.0.7827.53 or later. Users on Windows, macOS, and Linux should enable automatic updates or manually check Settings > About Google Chrome to trigger an update. Organizations managing Chrome at scale should use Chrome Enterprise policies to enforce this version constraint. Additionally, apply any available patches to operating systems and other browser-based applications to reduce the likelihood of renderer compromise in the first place.

Patch guidance

Google Chrome automatically checks for updates daily. Users can force an immediate check by navigating to Settings > About Google Chrome; the browser will download and install available updates and prompt for a restart. For enterprise environments, Chrome Enterprise administrators should verify that their managed instances have updated to 149.0.7827.53 or later and can use Version History reports to track compliance. Chromium-based browser vendors should be contacted or checked for coordinated patches released around the same timeframe as Chrome's fix.

Detection guidance

Monitor Chrome browser version inventory across your organization to identify instances below 149.0.7827.53. Browser telemetry and Mobile Device Management (MDM) solutions can help track deployed versions. Additionally, monitor web application logs for unusual IndexedDB access patterns or unexpected data modifications in applications that rely on local storage. Since the vulnerability requires prior renderer compromise, correlate any detected IndexedDB abuse with indicators of renderer process exploitation (e.g., abnormal process spawning, sandbox escape attempts, or other CVE activity).

Why prioritize this

Although the CVSS score of 5.3 places this in the MEDIUM range and no active exploitation is known, it warrants prompt remediation because it directly impacts web application data integrity and depends on an already-compromised renderer process. Organizations should prioritize this patch in the context of their renderer compromise defense strategy. The vulnerability is not an isolated flaw but rather one piece of a multi-stage attack chain; patching closes one link in that chain and reduces post-compromise damage. Standard Chrome auto-update mechanisms mean most users will be patched within days, but organizations with controlled update policies should treat this as a routine but important monthly patch.

Risk score, explained

The CVSS 3.1 score of 5.3 (MEDIUM) balances several factors: network-accessible attack vector (high base), high attack complexity due to renderer process prerequisite (reduces severity), no confidentiality impact (data accessed is not disclosed to attacker), high integrity impact (data can be modified), no availability impact, and unchanged scope. The moderate score appropriately reflects that this is a post-compromise vulnerability—useful to an attacker who has already breached the renderer, but not a direct entry point. Organizations should not underestimate this vulnerability solely on score; the integrity impact can be significant for data-critical web applications.

Frequently asked questions