FirefoxWeb browser · Mozilla
CVE-2019-9798
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 · uneditedOn Android systems, Firefox can load a library from APITRACE_LIB, which is writable by all users and applications. This could allow malicious third party applications to execute a man-in-the-middle attack if a malicious code was written to that location and loaded. *Note: This issue only affects Android. Other operating systems are unaffected.*. This vulnerability affects Firefox < 66.
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 confidenceFirefox on Android loads a library from a path specified by the APITRACE_LIB environment variable. Since this path is world-writable on Android, a malicious third-party application can place a crafted library there that Firefox will load, enabling a man-in-the-middle attack against the browser.
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
< 66.0CVSS 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
- None
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/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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Verify Firefox is installed on AndroidCheck if Mozilla Firefox is installed on the Android device. This vulnerability only affects Firefox on Android, not on desktop platforms.Affected if Firefox is installed on an Android device
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Check Firefox version on AndroidOpen Firefox on Android, navigate to Settings > Help > About Firefox to view the installed version number. Compare against the affected range: versions before 66.0 are vulnerable.Affected if Firefox version is below 66.0
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Check for APITRACE_LIB environment variableOn a rooted device or through ADB shell, run 'env | grep APITRACE_LIB' or check if the environment variable APITRACE_LIB is set on the Android system. This variable tells Firefox which library to load.Affected if APITRACE_LIB environment variable is set and points to a library path
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Check world-writable directory for suspicious librariesInspect the directory specified by the APITRACE_LIB path (commonly /data/data/local/tmp or similar world-writable locations on Android) for any unexpected shared library files (.so) that were not placed there by the user.Affected if A library file exists at the APITRACE_LIB path that was not intentionally placed there
A user is affected if they are running Firefox version below 66.0 on Android and the APITRACE_LIB environment variable is set on their device, allowing potential library injection from a malicious application.
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 data66.0
Upgrade Firefox to version 66 or later on all affected Android devices to prevent library injection attacks.
Fix this in Firefox
Scoped from the published advisory
- Consultation2.0 h
- Implementation3.0 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 $2,272.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2019-9798 — 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-2019-9798 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
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