FedoraOperating system · Fedoraproject
CVE-2016-6323
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 makecontext function in the GNU C Library (aka glibc or libc6) before 2.25 creates execution contexts incompatible with the unwinder on ARM EABI (32-bit) platforms, which might allow context-dependent attackers to cause a denial of service (hang), as demonstrated by applications compiled using gccgo, related to backtrace generation.
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 confidenceThe makecontext() function in glibc before 2.25 creates execution contexts on ARM EABI (32-bit) platforms that are incompatible with the unwinder, causing the backtrace() function to hang when called. This affects applications, particularly those compiled with gccgo, that use both makecontext and backtrace functionality.
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
FedoraOperating system
= 23= 24= 25<= 2.24= 13.2CVSS 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
- None
- Availability
- High
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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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Identify the system architectureRun 'uname -m' or check /proc/cpuinfo to confirm the system is running on 32-bit ARM (armv7l, armv6l, etc.)Affected if The architecture is not ARM EABI 32-bit - if running on x86_64, x86, aarch64, or other 64-bit architectures, this CVE does not apply
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Check installed glibc versionRun 'ldd --version' or check the output of 'rpm -q glibc' on Fedora/openSUSEAffected if The glibc version is 2.24 or lower. Versions 2.25 and later are not affected
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Verify the Linux distribution and versionCheck the OS release file (e.g., /etc/fedora-release or /etc/os-release) to identify the distribution versionAffected if Running Fedora 23, 24, or 25, or openSUSE 13.2, combined with ARM 32-bit architecture and glibc <= 2.24
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Identify if the application uses makecontext and backtraceReview application source code or use 'nm' and 'ldd' to check for linked libraries that call makecontext() and backtrace() functionsAffected if The application calls both makecontext() and backtrace() functions on a vulnerable ARM EABI 32-bit glibc version
A system is affected only if it runs on ARM EABI 32-bit architecture with glibc version 2.24 or lower AND runs an application that uses both makecontext() and backtrace() functionality, causing backtrace() to hang.
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 dataUpgrade glibc to version 2.25 or later on all affected ARM EABI (32-bit) systems to resolve the unwinder incompatibility.
Fix this in Fedora
Scoped from the published advisory
- Consultation3.0 h
- Implementation6.0 h
- Testing3.0 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 $3,984.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2016-6323 — 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-2016-6323 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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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
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