⚠ Reference material — not professional advice. Test in staging, back up first, verify against your specific version. Use your own judgment for your environment.
● High · CVSS 7.5

How to Fix CVE-2026-6756: Information disclosure in Firefox

By Sai Kiran Pandrala. Last verified: 2026-05-25.

⚡ At a glance
Severity7.5 (High)
Actively exploited?No public listing in CISA KEV
AffectedMozilla Firefox
Fixed inSee vendor advisory
Type (CWE)CWE-200: Exposure of Sensitive Information to an Unauthorized Actor

What is CVE-2026-6756?

Mitigation bypass in Firefox for Android. This vulnerability was fixed in Firefox 150.

Am I affected?

Run the version check that matches your platform:


# Android: Settings -> About phone -> Android version / Security patch level

Compare what you see against the Affected row above (Mozilla Firefox). If your build sits inside that range, you are exposed and should patch.

How to fix CVE-2026-6756

The primary fix is to upgrade Firefox to the patched build. Use the commands for your platform below; the patched version listed in the vendor advisory is: See vendor advisory.

Android

Open Settings -> System -> System update -> Check for update on the device, then install the security patch issued by the vendor (OEM or Google). On supported Pixel devices:


# Vendor advisory: https://bugzilla.mozilla.org/show_bug.cgi?id=1992585
# From a workstation with adb + the OTA package
adb sideload <android-patched-ota>.zip

If you can't patch immediately

If you cannot apply the patched version today, restrict exposure with one of the following runnable controls. None replace the patch.

Service-level fallback


# If the affected feature is optional, stop the service until the patch is applied
sudo systemctl stop firefox
sudo systemctl disable firefox

How to verify the fix worked


# Linux
firefox --version 2>/dev/null || dpkg -s firefox | grep -i version
rpm -q firefox 2>/dev/null || true


# Windows
winget list | findstr /I "firefox"
Get-HotFix | Sort-Object InstalledOn -Descending | Select-Object -First 5

Expected: the reported version is at or above the patched build documented in the advisory. Restart any services that loaded the old library (systemctl restart <service> on Linux, restart the Windows service or reboot when prompted). For network appliances, run show version on the device and confirm the build matches the patched release.

Frequently asked questions

Other vulnerabilities in the same area that are worth patching alongside this one:

Is CVE-2026-6756 actually being exploited?

According to the data sources above, no public confirmation of in-the-wild exploitation at this time. Either way, the fix is the same: apply the vendor patch.

Do I need to reboot after patching?

For OS or kernel updates, yes. For most userland packages a systemctl restart <service> is enough. Any process that loaded the old shared library keeps using it until restarted, so when in doubt, reboot.

What is the CVSS score?

7.5 (high). Refer to the vendor advisory for the exact vector string.

Where is the official advisory?

See the References section at the bottom of this page; the vendor's URL is the authoritative source for affected builds and patched versions.

References

*Written by Sai Kiran Pandrala. Assembled from the official vendor advisory, NVD record, and CISA KEV listing on 2026-05-25. Always confirm against the vendor's advisory before applying changes in production.*