FirefoxWeb browser · Mozilla
CVE-2025-1014
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 · uneditedCertificate length was not properly checked when added to a certificate store. In practice only trusted data was processed. This vulnerability was fixed in Firefox 135, Firefox ESR 128.7, Thunderbird 128.7, and Thunderbird 135.
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 confidenceCertificate length validation was missing when adding certificates to the certificate store in Firefox and Thunderbird. This could allow improperly crafted certificates to be accepted. The vendor notes that in practice only trusted data was processed, limiting real-world impact.
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
< 128.7.0< 135.0>= 128.0.1, < 128.7.0>= 131.0, < 135.0CVSS 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
- 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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Check Firefox versionOpen Firefox, click the menu (three bars) > Help > About Firefox. The version number is displayed on this page.Affected if The displayed version is below 128.7.0 or is between 128.7.0 and 134.x (below 135.0)
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Check Thunderbird versionOpen Thunderbird, click the menu (three lines) > Help > About Thunderbird. The version number is displayed on this page.Affected if The displayed version is 128.0.1 or above but below 128.7.0, OR is 131.0 or above but below 135.0
You are affected if you run any version of Firefox below 135.0 (with the threshold being 128.7.0 for the ESR branch) or any version of Thunderbird in the ranges 128.0.1 to 128.6.x or 131.0 to 134.x
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 · scoped128.7.0135.0
Update affected installations to Firefox 135+, Firefox ESR 128.7+, Thunderbird 128.7+, or Thunderbird 135+ to remediate this vulnerability.
Firefox 135 (regular) or Firefox ESR 128.7.0 (ESR); Thunderbird 135 (regular) or Thunderbird 128.7 (ESR)
- Check current Firefox version: Open Firefox, go to Help > About Firefox (or navigate to about:support)
- Check current Thunderbird version: Open Thunderbird, go to Help > About Thunderbird
- For Firefox: Navigate to https://www.mozilla.org/en-US/firefox/releases/ to download Firefox 135 (or Firefox ESR 128.7 for ESR users)
- For Thunderbird: Navigate to https://www.mozilla.org/en-US/thunderbird/releases/ to download Thunderbird 135 (or Thunderbird 128.7 for ESR users)
- Download and install the appropriate fixed version matching your product and branch (Regular or ESR)
- Restart the application after upgrade
- Verify the version by checking Help > About to confirm you are on 135.0 or 128.7.0 respectively
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
- Testing4.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,120.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2025-1014 — 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-2025-1014 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