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CVE Record

CVE-2019-20636: In the Linux kernel before 5.4.12, drivers/input/input.c has out-of-bounds writes via a crafted keycode tab...

In the Linux kernel before 5.4.12, drivers/input/input.c has out-of-bounds writes via a crafted keycode table, as demonstrated by input_set_keycode, aka CID-cb222aed03d7.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

CVE-2019-20636 is a Linux kernel memory-safety flaw in the input subsystem before version 5.4.12. A crafted keycode table could trigger out-of-bounds writes. This matters most for systems running older or vendor-derived kernels, including appliances and long-term-support distributions that had to ship security updates.

Executive priority

Treat this as a kernel hygiene and lifecycle item unless vendor guidance raises product-specific urgency. The business priority is reducing exposure from old or unsupported Linux kernels, especially where appliances cannot be independently patched.

Technical view

The issue is in drivers/input/input.c, where input_set_keycode handling could write outside expected bounds when processing a crafted keycode table. The public record associates the fix with Linux commit cb222aed03d798fc074be55e59d9a112338ee784 and inclusion in Linux 5.4.12-related changelog material.

Likely exposure

Exposure is likely limited to Linux systems or products using affected pre-5.4.12 kernel code before vendor backports. Debian LTS and NetApp references show downstream vendors evaluated or shipped guidance, but the provided bundle does not enumerate exact affected products or configurations.

Exploitation context

The provided sources do not show active exploitation, and the CVE is not listed as CISA KEV. They describe the bug class and fix lineage, but do not establish public exploit availability, remote reachability, or required privileges.

Researcher notes

Evidence supports an out-of-bounds write in Linux input keycode handling fixed upstream, but the bundle lacks CVSS, CWE, exploitability details, and affected product matrices. Avoid assuming remote exploitation or universal Linux exposure without local kernel provenance and vendor backport confirmation.

Mitigation direction

  • Upgrade to a vendor kernel containing the upstream fix or equivalent backport.
  • For Linux 5.4-based systems, ensure fixes at or beyond 5.4.12 are applied.
  • Check Debian LTS and appliance vendor advisories for supported patched packages.
  • Prioritize unsupported kernels and embedded appliances for vendor-specific remediation review.

Validation and detection

  • Inventory Linux kernel versions across servers, endpoints, containers hosts, and appliances.
  • Confirm vendor kernel changelogs mention CVE-2019-20636 or commit cb222aed03d7.
  • Verify Debian LTS systems received the relevant DLA kernel security update.
  • Ask appliance vendors whether their shipped kernel includes an equivalent backport.
Prepared
Confidence
medium
Sources
7

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

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CVE-2019-20636 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
0Timeline events
0ADP providers
7Source links

CVSS and timeline data

No CVSS vectors or timeline events were available in the normalized CVE source material.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
n/an/an/aListed
Weakness

CWE details

No CWE listed

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.