FirefoxWeb browser · Mozilla
CVE-2026-5733
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedIncorrect boundary conditions in the Graphics: WebGPU component. This vulnerability was fixed in Firefox 149.0.2 and Thunderbird 149.0.2.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · moderate confidenceA boundary condition vulnerability exists in the WebGPU graphics component of Firefox and Thunderbird. Incorrect boundary conditions typically indicate improper bounds checking when accessing memory buffers or arrays, which could allow out-of-bounds memory access. This was addressed in Firefox 149.0.2 and Thunderbird 149.0.2.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data
FirefoxWeb browser
< 149.0.2CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Confirm Firefox installationCheck if Firefox is installed by looking for the executable. On Windows, check C:\Program Files\Mozilla Firefox\firefox.exe. On macOS, check /Applications/Firefox.app. On Linux, run 'which firefox' or check /usr/lib/firefox/Affected if Firefox is not installed on the system
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Determine installed Firefox versionIn Firefox, navigate to Help > About Firefox, or run 'firefox --version' from command line on Linux. On Windows, you can also check the file properties of firefox.exeAffected if The installed version is below 149.0.2 (any version from 1.0 through 149.0.1)
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Check WebGPU enablement statusIn Firefox, type 'about:config' in the address bar, search for 'webgpu.enabled', or check if WebGPU is accessible via the browser's configuration settings. On Linux, you may also check the profiles.ini or pref.js files for WebGPU-related preferencesAffected if WebGPU is enabled (the vulnerability exists in the WebGPU component, so it only affects systems where WebGPU is turned on)
The system is affected if Firefox is installed with a version lower than 149.0.2 AND WebGPU is enabled in the browser settings
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scoped149.0.2
Upgrade to Firefox 149.0.2 or Thunderbird 149.0.2 or later. Organizations using WebGPU should prioritize patching given the high CVSS score.
Firefox 149.0.2
- 1. Check current Firefox version by navigating to Menu > Help > About Firefox
- 2. If the version is below 149.0.2, download Firefox 149.0.2 or later from the official Mozilla website (www.mozilla.org)
- 3. Install the updated version, which will include the fix for the WebGPU boundary condition vulnerability (CVE-2026-5733)
- 4. Restart Firefox after the update completes
- 5. Verify the version now shows 149.0.2 or higher
Generated from the published advisory — verify against the referenced sources before acting.
Fix this in Firefox
Scoped from the published advisory
- Consultation2.0 h
- Implementation4.0 h
- Testing6.0 h
- Review / QA3.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,096.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-5733 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-5733 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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