Enterprise Linux DesktopOperating system · Redhat
CVE-2016-3099
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 · uneditedmod_ns in Red Hat Enterprise Linux Desktop 7, Red Hat Enterprise Linux HPC Node 7, Red Hat Enterprise Linux Server 7, and Red Hat Enterprise Linux Workstation 7 allows remote attackers to force the use of ciphers that were not intended to be enabled.
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 confidencemod_ns module in Red Hat Enterprise Linux 7 allows remote attackers to force the use of ciphers that were not intended to be enabled, potentially weakening TLS/SSL encryption by enabling weaker or unintended cryptographic algorithms.
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
Enterprise Linux DesktopOperating system
= 7.0
Enterprise Linux Hpc NodeOperating system
= 7.0
Enterprise Linux ServerOperating system
= 7.0
Enterprise Linux WorkstationOperating system
= 7.0CVSS 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
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- High
- Availability
- None
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/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.
-
Verify if mod_ns module is installedRun 'rpm -qa | grep -i mod_ns' to check if the mod_ns package is installed on the systemAffected if The mod_ns package is present on the system
-
Check if mod_ns is loaded in ApacheRun 'httpd -M 2>/dev/null | grep ns' or inspect Apache configuration files in /etc/httpd/conf.d/ for 'LoadModule ns_module' statementsAffected if mod_ns module is loaded or configured to load in Apache
-
Identify mod_ns cipher configurationSearch Apache configuration files (especially /etc/httpd/conf.d/*.conf) for 'NSSCipherSuite' or 'NSSProtocol' directives that control cipher selectionAffected if Cipher configuration directives (NSSCipherSuite) exist in the Apache configuration for mod_ns
-
Review enabled cipher suitesExamine the cipher suite strings in NSSCipherSuite directives and compare them against known weak or unintended ciphers (such as export-grade ciphers, NULL encryption, or MD5-based suites)Affected if Weak, export-grade, or unintended ciphers are explicitly enabled in the mod_ns cipher configuration
-
Check if TLS/SSL is actively served via mod_nsCheck if Apache is configured to listen on ports 443 (https) and if mod_ns SSL/TLS directives are in use by examining configuration files and running 'ss -tlnp | grep :443'Affected if Apache is serving HTTPS traffic using the mod_ns module with the vulnerable cipher configuration
The system is affected if mod_ns is installed, loaded in Apache, and configured with TLS/SSL using cipher settings that permit weak or unintended cryptographic algorithms.
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 dataReview and restrict the cipher suite configuration in mod_ns to ensure only strong, intended ciphers are enabled; disable any unintended or weak ciphers in the Apache configuration.
Fix this in Enterprise Linux Desktop
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-2016-3099 — 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-2016-3099 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
Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.
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