FirefoxWeb browser · Mozilla
CVE-2026-2806
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 · uneditedUninitialized memory in the Graphics: Text component. This vulnerability was fixed in Firefox 148 and Thunderbird 148.
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 confidenceMemory corruption vulnerability in the Graphics: Text rendering component where memory is used before being properly initialized, potentially allowing arbitrary code execution or sensitive information disclosure.
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
< 148.0< 148.0CVSS 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
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/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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Check Firefox versionOpen Firefox, navigate to Help > About Firefox, or run 'firefox --version' from command line. Note the displayed version number.Affected if Version is below 148.0 (for example, 147.x, 147.0.x, or any earlier version)
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Check Thunderbird versionOpen Thunderbird, navigate to Help > About Thunderbird, or run 'thunderbird --version' from command line. Note the displayed version number.Affected if Version is below 148.0 (for example, 147.x, 147.0.x, or any earlier version)
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Confirm which affected product is in useIdentify whether Firefox or Thunderbird (or both) are installed on the system by checking installed applications or running the version commands above.Affected if Either product is present with a version below 148.0
A user is affected if they have Mozilla Firefox or Thunderbird installed with any version number below 148.0, as the vulnerability exists in the text rendering component of those unpatched versions.
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 · scoped148.0
Update to Firefox 148 or Thunderbird 148 to obtain the patched version. Until patched, limit exposure by disabling text rendering features or restricting access to untrusted content.
Firefox 148.0 and Thunderbird 148.0
- Check current Firefox version by navigating to Menu > Help > About Firefox
- Check current Thunderbird version by navigating to Menu > Help > About Thunderbird
- For Firefox: Open Menu > Help > About Firefox > Click 'Check for Updates' to download and install version 148.0 or later
- For Thunderbird: Open Menu > Help > About Thunderbird > Click 'Check for Updates' to download and install version 148.0 or later
- Restart the application after the update completes
- Verify the update was successful by checking the version number again
Generated from the published advisory — verify against the referenced sources before acting.
Fix this in Firefox
Scoped from the published advisory
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA4.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $6,176.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-2806 — 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-2026-2806 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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A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.
- 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
- No spam, self-promotion, credentials, or personal data