CVE-2026-7933: Google Chrome Buffer Overflow Vulnerability

CVE-2026-7933 Overview

CVE-2026-7933 is an out-of-bounds read vulnerability [CWE-125] in the WebCodecs component of Google Chrome versions prior to 148.0.7778.96. A remote attacker can trigger an out-of-bounds memory read by serving a crafted video file to a victim browser. Chromium classifies the security severity as Medium. Exploitation requires user interaction, such as visiting a malicious page or opening a crafted media resource. Successful exploitation leaks small amounts of process memory but does not, on its own, modify data or cause a crash. The flaw affects Chrome on Windows, macOS, and Linux.

Critical Impact

Remote attackers can read out-of-bounds process memory in Chrome's WebCodecs component by delivering a crafted video file, exposing potentially sensitive in-process data.

Affected Products

• Google Chrome prior to 148.0.7778.96
• Microsoft Windows (Chrome desktop builds)
• Apple macOS and Linux (Chrome desktop builds)

Discovery Timeline

• 2026-05-06 - CVE-2026-7933 published to NVD
• 2026-05-06 - Last updated in NVD database

Technical Details for CVE-2026-7933

Vulnerability Analysis

The vulnerability exists in WebCodecs, the Chromium API that exposes low-level access to built-in audio and video encoders and decoders to web content. WebCodecs parses container metadata and codec-specific frames before handing buffers to the underlying media pipeline. CVE-2026-7933 is an out-of-bounds read [CWE-125] triggered when WebCodecs processes a malformed video file. The component reads memory beyond the bounds of a valid buffer during decoding or frame description handling. The read does not corrupt memory, but it returns adjacent process memory to renderer-controlled code paths. Attackers can use this primitive to leak data such as pointers, partial heap contents, or cross-origin media bytes that aid in defeating Address Space Layout Randomization (ASLR) or staging follow-on exploits.

Root Cause

The root cause is missing or insufficient bounds checking on attacker-controlled length, offset, or sample-size fields parsed from a crafted video file inside WebCodecs. When the parser trusts these fields, subsequent buffer reads extend past the end of the allocated region. Refer to the Chromium Issue Tracker Entry for component-level technical details.

Attack Vector

Exploitation is network-based and requires user interaction. A target must load a page that uses WebCodecs to decode an attacker-supplied video, or open a crafted media resource hosted by the attacker. No privileges are required on the victim system. The attack is constrained to information disclosure and does not directly affect integrity or availability. Confidentiality impact is limited to data accessible from the renderer process at the moment of exploitation. No public proof-of-concept or in-the-wild exploitation has been reported, and the issue is not listed in the CISA Known Exploited Vulnerabilities catalog.

Detection Methods for CVE-2026-7933

Indicators of Compromise

• Chrome browser builds reporting a version older than 148.0.7778.96 in enterprise inventory or chrome://version.
• Renderer process crashes or anomalous memory access events tied to the WebCodecs or media modules following video playback.
• Web traffic delivering unusual or malformed video containers (for example, MP4 or WebM) to endpoints from low-reputation domains.

Detection Strategies

• Inventory installed Chrome versions across managed endpoints and flag any host below 148.0.7778.96.
• Inspect endpoint detection telemetry for renderer child processes (chrome.exe --type=renderer) exhibiting access violations after media decode operations.
• Correlate web proxy or DNS logs with endpoint browser sessions that fetched untrusted video content immediately before suspicious renderer behavior.

Monitoring Recommendations

• Ingest browser version telemetry into the SIEM and alert on stale Chrome installs after the patch release.
• Monitor for outbound connections to newly registered or low-reputation domains hosting media content.
• Track renderer crash dumps referencing WebCodecs symbols to identify exploitation attempts or unstable crafted-media payloads.

How to Mitigate CVE-2026-7933

Immediate Actions Required

• Update Google Chrome to version 148.0.7778.96 or later on Windows, macOS, and Linux endpoints.
• Force a managed restart of Chrome after deployment so the patched binary is loaded by all renderer processes.
• Verify update compliance using browser version reporting and enforce minimum-version policies through enterprise management.

Patch Information

Google addressed CVE-2026-7933 in the Stable channel update that ships Chrome 148.0.7778.96. Apply the official build documented in the Google Chrome Desktop Update advisory. Chromium-based browsers that consume the same upstream fix should be updated to a build that incorporates the patched WebCodecs source.

Workarounds

• Restrict access to untrusted media content through web proxy categorization and URL filtering until patching is complete.
• Use enterprise policy to disable or limit experimental web platform features where feasible, reducing exposure of WebCodecs to unvetted origins.
• Enforce site isolation and standard sandboxing settings so that any leaked memory remains scoped to the renderer of the offending origin.

# Configuration example: enforce minimum Chrome version via Group Policy (Windows)
# Registry path:
#   HKLM\Software\Policies\Google\Chrome\TargetVersionPrefix
reg add "HKLM\Software\Policies\Google\Chrome" /v TargetVersionPrefix /t REG_SZ /d "148.0.7778.96" /f

# Verify installed version
reg query "HKLM\Software\Google\Update\Clients\{8A69D345-D564-463C-AFF1-A69D9E530F96}" /v pv