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PatchSiren cyber security CVE debrief

CVE-2026-9939 Google CVE debrief

A heap buffer overflow in Google Chrome's WebCodecs API allows remote code execution inside the sandbox when a user visits a crafted HTML page. Google rated this High severity and patched it in Chrome 148.0.7778.216. The vulnerability was published in the NVD on 28 May 2026 and last modified on 29 May 2026. No known exploitation in ransomware campaigns has been catalogued by CISA KEV.

Vendor
Google
Product
Chrome
CVSS
HIGH 8.8
CISA KEV
Not listed in stored evidence
Original CVE published
2026-05-28
Original CVE updated
2026-07-21
Advisory published
2026-05-28
Advisory updated
2026-07-21

Who should care

End users, desktop administrators, and security teams managing browser deployments in enterprise environments should prioritize this update due to the High severity and potential for remote code execution through user-facing web content.

Technical summary

The vulnerability exists in Chrome's implementation of the WebCodecs API, a web platform interface for encoding and decoding audio and video. A heap-based buffer overflow can be triggered by a maliciously crafted HTML page, leading to arbitrary code execution within the Chrome sandbox. Successful exploitation requires a user to render the attacker-controlled page. The issue was resolved in Chrome 148.0.7778.216.

Defensive priority

high

Recommended defensive actions

  • Update Google Chrome to version 148.0.7778.216 or later across all supported platforms (Windows, macOS, Linux).
  • Verify automatic update channels are enabled for Chrome in enterprise deployments.
  • Restrict or monitor navigation to untrusted web content until patching is complete, as exploitation requires user interaction with a malicious page.
  • Review application logs for unexpected renderer crashes or sandbox escape indicators that may suggest attempted exploitation.

Evidence notes

The NVD entry lists CWE-122 (Heap-based Buffer Overflow) and CVSS 3.1 vector AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H scoring 8.8. CPE configurations show affected Chrome versions prior to 148.0.7778.216 on Windows, macOS, and Linux.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-9939 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-9939

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-9939 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-9939

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.