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Linux KernelOperating system · Linux

CVE-2016-7042

MEDIUM · 6.2 CVSS v3.0 Published 2016-10-16
Fix available
A fix is available. Upgrade to after 4.8.2 or later.
See remediation →
67/100
Remediation priority · Elevated
No privileges Zero-click

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 · unedited
The proc_keys_show function in security/keys/proc.c in the Linux kernel through 4.8.2, when the GNU Compiler Collection (gcc) stack protector is enabled, uses an incorrect buffer size for certain timeout data, which allows local users to cause a denial of service (stack memory corruption and panic) by reading the /proc/keys file.

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 confidence

The proc_keys_show function in security/keys/proc.c in Linux kernel through 4.8.2 uses an incorrect buffer size for timeout data when GCC stack protector is enabled, causing stack memory corruption when local users read the /proc/keys file, leading to denial of service via kernel panic.

MitigationApply the kernel patch correcting the buffer size calculation in proc_keys_show, or upgrade to a kernel version beyond 4.8.2 that contains the fix.

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
Linux KernelOperating system
Affected:<= 4.8.2

CVSS 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
Local
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.0/AV:L/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 checks

Work through these to decide whether this CVE applies to you.

  1. Check kernel version
    Run 'uname -r' or 'cat /proc/version' to identify the installed kernel version
    Affected if Kernel version is 4.8.2 or earlier (any version <= 4.8.2)
  2. Verify GCC stack protector is enabled in kernel
    Check kernel configuration file (usually /boot/config-$(uname -r) or /proc/config.gz) for CONFIG_CC_STACKPROTECTOR or CONFIG_CC_STACKPROTECTOR_STRONG options - if set to 'y', stack protector is enabled
    Affected if Kernel was built with stack protector enabled (CONFIG_CC_STACKPROTECTOR=y or CONFIG_CC_STACKPROTECTOR_STRONG=y)
  3. Confirm /proc/keys accessibility
    Run 'ls -la /proc/keys' to verify the file exists and is readable by the checking user
    Affected if The /proc/keys file exists and is readable (typically readable by all users)
  4. Check if keys are present in the system
    Run 'cat /proc/keys' to see if any registered keys are listed - the vulnerable code path is exercised when displaying key timeout data
    Affected if Any keys are registered in the system (output of /proc/keys shows entries with timeout values)

The environment is affected if the kernel version is 4.8.2 or earlier, the kernel was compiled with GCC stack protector enabled, and the /proc/keys file can be read (which is typically world-readable).

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 data
Upgrade available Upgrade to a release after 4.8.2
Interim mitigation

Apply the kernel patch correcting the buffer size calculation in proc_keys_show, or upgrade to a kernel version beyond 4.8.2 that contains the fix.

Fix this in Linux Kernel Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing4.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,080
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Scan for this in your stack

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2016-7042 in production — separate from our analysis above.

No notes yet

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What this is

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.

What belongs here
  • 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