CVE-2026-9903: Insufficient validation of untrusted input in Site Isolation
Chromium: CVE-2026-9903 Insufficient validation of untrusted input in Site Isolation
Other sources
Insufficient validation of untrusted input in Site Isolation in Google Chrome prior to 148.0.7778.216 allowed a remote attacker who had compromised the renderer process to bypass site isolation via a crafted MHTML page. (Chromium security severity: High)
— NVD
This CVE was assigned by Chrome. Microsoft Edge (Chromium-based) ingests Chromium, which addresses this vulnerability. Please see Google Chrome Releases for more information.
— Microsoft
Credit
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
Chromium/Google Chrometo a version that resolves this vulnerability.Fixed in 148.0.7778.216 - Upgrade
Upgrade
Microsoft Edge (Chromium-based)to a version that resolves this vulnerability.Fixed in 148.0.7778.216
Event History
Peer vulnerabilities
Found alongside the following vulnerabilities.
- CVE-2026-12034
- CVE-2026-7922
- CVE-2026-13033
- CVE-2026-9970
- CVE-2026-10969
- CVE-2026-10003
- CVE-2026-9933
- CVE-2026-9993
- CVE-2026-9961
- CVE-2026-9995
- CVE-2026-12439
- CVE-2026-10905
- CVE-2026-8557
- CVE-2026-7339
- CVE-2026-8559
- CVE-2026-6920
- CVE-2026-8524
- CVE-2026-10007
- CVE-2026-12008
- CVE-2026-12440
- CVE-2026-6360
- CVE-2026-12441
- CVE-2026-7348
Frequently Asked Questions
What is the severity of CVE-2026-9903?
The severity of CVE-2026-9903 is rated as medium with a score of 5 according to the CVSS 3.1.
How do I fix CVE-2026-9903?
To fix CVE-2026-9903, users should update Google Chrome or Microsoft Edge to the latest version, specifically to 148.0.7778.216 or later.
What is the impact of CVE-2026-9903?
CVE-2026-9903 allows a remote attacker who has compromised the renderer process to bypass site isolation, potentially leading to unauthorized access to sensitive data.
Which software is affected by CVE-2026-9903?
CVE-2026-9903 affects Google Chrome and Microsoft Edge (Chromium-based) prior to version 148.0.7778.216.
What type of vulnerability is CVE-2026-9903?
CVE-2026-9903 is classified as an input validation vulnerability related to insufficient validation of untrusted input in Site Isolation.