CVE-2016-8671
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 · uneditedThe pstm_exptmod function in MatrixSSL 3.8.6 and earlier does not properly perform modular exponentiation, which might allow remote attackers to predict the secret key via unspecified vectors. NOTE: this vulnerability exists because of an incomplete fix for CVE-2016-6887.
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 confidenceThe pstm_exptmod function in MatrixSSL 3.8.6 and earlier contains a flaw in modular exponentiation that could allow prediction of secret keys. This is a regression from an incomplete fix for CVE-2016-6887, indicating the underlying mathematical implementation remains flawed.
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<= 3.8.6CVSS 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
- None
- Availability
- None
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/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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Confirm MatrixSSL is installedSearch for MatrixSSL libraries or header files in your system common paths (/usr/lib, /usr/local/lib, or via package manager query)Affected if MatrixSSL library files are found on the system
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Determine installed MatrixSSL versionRun 'strings' on the MatrixSSL library file and search for version strings, or check the library filename if it contains version info, or query your package manager if installed via packagesAffected if The version string shows 3.8.6 or any earlier version (e.g., 3.8.5, 3.8.4, etc.)
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Identify applications using MatrixSSLUse 'ldd' on executables or 'grep' for MatrixSSL import symbols to find which applications link against the libraryAffected if Any application is linked to a MatrixSSL library version 3.8.6 or earlier
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Check for RSA key operationsReview application code or configuration for use of RSA encryption, decryption, or key generation functions provided by MatrixSSLAffected if The application performs RSA operations (key generation, encryption, decryption) using the vulnerable MatrixSSL library
You are affected if MatrixSSL version 3.8.6 or earlier is installed and any application performs RSA cryptographic operations using that library.
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 dataUpdate MatrixSSL to a version beyond 3.8.6 that contains the complete fix for this cryptographic vulnerability, or implement additional validation layers if immediate updates are not feasible.
- 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-2016-8671 — 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-2016-8671 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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