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Linux KernelOperating system · Linux

CVE-2023-31081

MEDIUM · 5.5 CVSS v3.1 Published 2023-04-24
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
57/100
Remediation priority · Elevated
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
An issue was discovered in drivers/media/test-drivers/vidtv/vidtv_bridge.c in the Linux kernel 6.2. There is a NULL pointer dereference in vidtv_mux_stop_thread. In vidtv_stop_streaming, after dvb->mux=NULL occurs, it executes vidtv_mux_stop_thread(dvb->mux).

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

A NULL pointer dereference vulnerability exists in the Linux kernel's vidtv test driver (vidtv_bridge.c). The function vidtv_stop_streaming sets dvb->mux to NULL and then immediately calls vidtv_mux_stop_thread(dvb->mux), which attempts to dereference the NULL pointer, causing a kernel crash.

MitigationSince this is a test driver in drivers/media/test-drivers, the simplest mitigation is to disable the vidtv driver in the kernel configuration or not load it in production environments. The upstream fix would add a NULL check before calling vidtv_mux_stop_thread().

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:= 6.2

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
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/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 The kernel version is 6.2.x (e.g., 6.2.0, 6.2.1, etc.)
  2. Verify vidtv driver presence in kernel
    Check /boot/config-'uname -r' for 'CONFIG_MEDIA_VIDTV=m' (module) or 'CONFIG_MEDIA_VIDTV=y' (built-in), or run 'lsmod | grep vidtv' to see if the module is loaded
    Affected if The vidtv driver is compiled as built-in ('=y') or currently loaded as a module ('=m' or appears in lsmod)
  3. Confirm driver is in use
    Check /sys/module/vidtv/holders and /sys/class/video4linux/ for vidtv device nodes, or check dmesg for vidtv-related messages
    Affected if The driver has been initialized and created device nodes or logged messages indicating it is active

A system is affected if it runs kernel 6.2.x AND has the vidtv driver enabled or loaded, as the NULL pointer dereference occurs when vidtv_stop_streaming is called with the driver active.

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.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Since this is a test driver in drivers/media/test-drivers, the simplest mitigation is to disable the vidtv driver in the kernel configuration or not load it in production environments. The upstream fix would add a NULL check before calling vidtv_mux_stop_thread().

Recommended fix Moderate confidence

Linux Kernel 6.3 or later (or appropriate stable backport such as 6.2.x stable that includes the fix)

  1. 1. Identify the current kernel version using: uname -r
  2. 2. Check if the system is running kernel 6.2.x: uname -r | grep '^6\.2'
  3. 3. Upgrade to a kernel version that includes the fix for this NULL pointer dereference (kernel 6.3 or later, or a stable backport that includes the fix)
  4. 4. Reboot the system into the new kernel
  5. 5. Verify the fix is applied by checking the vidtv_bridge.c file in /usr/src/linux or by confirming the NULL pointer dereference no longer occurs in dmesg
Caveat Upgrading kernel versions may require rebooting and could have compatibility implications with custom drivers or modules

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Linux Kernel Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing2.0 h
  • Review / QA1.0 h
7.0 hours of engineering $1,240
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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-2023-31081 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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