Firefox MobileWeb browser · Mozilla
CVE-2020-26957
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 · uneditedOneCRL was non-functional in the new Firefox for Android due to a missing service initialization. This could result in a failure to enforce some certificate revocations. *Note: This issue only affected Firefox for Android. Other operating systems are unaffected.*. This vulnerability affects Firefox < 83.
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 · high confidenceOneCRL certificate revocation checking was non-functional in Firefox for Android versions prior to 83 due to a missing service initialization. This meant the browser could not properly enforce certificate revocations, potentially allowing connections to servers using revoked or compromised certificates.
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
Firefox MobileWeb browser
< 83.0CVSS 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
- Required
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- High
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
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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Identify the browser applicationConfirm you are using Mozilla Firefox for Android, not desktop Firefox or another browser. Check the app name in your device's app settings or the app icon.Affected if The target is any version of Firefox for Android, as this CVE affects only the Android platform.
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Locate Firefox for Android versionOpen the Google Play Store app, search for 'Firefox', tap on the installed Firefox app, and view the version number displayed under the app name. Alternatively, go to Settings > Apps > Firefox > App info to see the version.Affected if Version information cannot be retrieved, but the app is Firefox for Android.
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Compare installed version against affected rangeExamine the version number obtained from the previous step. The affected range for CVE-2020-26957 is any version prior to 83.0.Affected if The installed version is below 83.0 (for example, 82.0, 81.0, 80.0, etc.). Versions 83.0 and later are not affected.
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Verify OneCRL functionality impactThis CVE describes a missing service initialization that prevented OneCRL certificate revocation checking from functioning. The vulnerability is version-based; if the version is below 83.0, the OneCRL revocation checking is non-functional by design.Affected if Firefox for Android version is below 83.0, meaning the certificate revocation enforcement is not working as intended.
You are affected if you are running Mozilla Firefox for Android with a version number less than 83.0 on your device.
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.
From vendor data83.0
Update Firefox for Android to version 83 or later to restore OneCRL functionality and proper certificate revocation enforcement.
Fix this in Firefox Mobile
Scoped from the published advisory
- Consultation1.0 h
- Testing1.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,200.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-26957 — 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-2020-26957 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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