CVE-2026-9939

Description

Heap buffer overflow in WebCodecs in Google Chrome prior to 148.0.7778.216 allowed a remote attacker to execute arbitrary code inside a sandbox via a crafted HTML page. (Chromium security severity: High)

CVSS v3.1 Score

8.8

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

EPSS — Exploit Prediction

0.0043

Probability of exploitation

0.34%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-122 CWE-122

Affected Products

Vendor	Product	Versions
google	chrome	< 148.0.7778.216
microsoft	windows	All
google	chrome	< 148.0.7778.215
apple	macos	All
linux	linux_kernel	All

References

Advisories & Patches

https://chromereleases.googleblog.com/2026/05/stable-channel-update-for-desktop_0877304591.html

Other References

https://issues.chromium.org/issues/502735235

Frequently Asked Questions

What is CVE-2026-9939? +

Heap buffer overflow in WebCodecs in Google Chrome prior to 148.0.7778.216 allowed a remote attacker to execute arbitrary code inside a sandbox via a crafted HTML page. (Chromium security severity: High) It has a CVSS v3.1 base score of 8.8 (HIGH).

How severe is CVE-2026-9939? +

CVE-2026-9939 has a CVSS v3.1 score of 8.8 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0043, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-9939? +

CVE-2026-9939 affects products from apple, google, linux, microsoft, specifically: chrome, linux_kernel, macos, windows. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-9939? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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