FirefoxWeb browser · Mozilla
CVE-2025-3030
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 · uneditedMemory safety bugs present in Firefox 136, Thunderbird 136, Firefox ESR 128.8, and Thunderbird 128.8. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability was fixed in Firefox 137, Firefox ESR 128.9, Thunderbird 137, and Thunderbird 128.9.
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 confidenceMemory safety bugs in Firefox 136 and Thunderbird 136 (and ESR versions 128.8) that could allow memory corruption and potentially arbitrary code execution via carefully crafted web content. The specific memory corruption types are not detailed but are typical of Firefox's memory safety class vulnerabilities.
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
< 128.8.0< 136.0< 128.8.0>= 129.0, < 136.0CVSS 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
- High
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/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, go to Help > About Firefox, or navigate to about:support, or run: firefox --versionAffected if Version is below 128.8.0 or between 128.8.0 and 135.x (any version below 136.0)
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Check Thunderbird versionOpen Thunderbird, go to Help > About Thunderbird, or run: thunderbird --versionAffected if Version is below 128.8.0 or between 129.0 and 135.x (any version below 136.0 but at or above 129.0)
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Verify web content handling is enabledConfirm that Firefox or Thunderbird has JavaScript enabled and can render HTML email or web content. Default installations allow this.Affected if The application renders web content or HTML email, which is the default behavior
You are affected if Firefox is any version below 136.0, or Thunderbird is any version below 128.8.0 or between 129.0 and 135.x, and the application renders web/HTML content (default 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 · scoped128.8.0136.0
Upgrade immediately to Firefox 137, Firefox ESR 128.9, Thunderbird 137, or Thunderbird 128.9. Organizations should deploy the updates via their standard patch management processes and verify completion across all affected endpoints.
Firefox 137, Firefox ESR 128.9, Thunderbird 137, or Thunderbird 128.9 (depending on which product and channel is in use)
- Upgrade Firefox to version 137 or later
- Upgrade Firefox ESR to version 128.9 or later
- Upgrade Thunderbird to version 137 or later
- Upgrade Thunderbird to version 128.9 or later
Generated from the published advisory — verify against the referenced sources before acting.
Fix this in Firefox
Scoped from the published advisory
- Consultation2.0 h
- Implementation1.0 h
- Testing2.0 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 $1,696.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2025-3030 — 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-2025-3030 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