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Linux KernelOperating system · Linux

CVE-2021-38160

HIGH · 7.8 CVSS v3.1 Published 2021-08-07
Fix available
A fix is available. Upgrade to 4.4.276 / 4.9.276 or later.
See remediation →
80/100
Remediation priority · High
Zero-click Patch available

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
In drivers/char/virtio_console.c in the Linux kernel before 5.13.4, data corruption or loss can be triggered by an untrusted device that supplies a buf->len value exceeding the buffer size. NOTE: the vendor indicates that the cited data corruption is not a vulnerability in any existing use case; the length validation was added solely for robustness in the face of anomalous host OS behavior

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
How this class of weakness works · CWE-120

A fixed-size buffer is filled without checking the length of the incoming data, so it overflows into neighbouring memory. This is the classic overflow attackers use to overwrite return addresses and hijack execution. The fix is strict length checks and safe, bounded string and memory functions.

General guidance for the classic buffer overflow class — the official description and references above are authoritative for this specific CVE. Want a bespoke review and a reviewed fix? Ask our team →

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:>= 2.6.24, < 4.4.276>= 4.5, < 4.9.276>= 4.10, < 4.14.240>= 4.15, < 4.19.198>= 4.20, < 5.4.134>= 5.5, < 5.10.52>= 5.11, < 5.12.19>= 5.13, < 5.13.4
Debian LinuxOperating system
Affected:= 9.0= 10.0
Enterprise LinuxOperating system
Affected:= 8.0
Hci Bootstrap OsOperating system
Affected:all versions
Hci Management NodeApplication
Affected:all versions
SolidfireApplication
Affected:all versions
Element SoftwareApplication
Affected:all versions

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
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

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
Upgrade available Upgrade to 4.4.276 / 4.9.276 / 4.14.240 or later
Fixed in 4.4.2764.9.2764.14.240
Vendor patch github.com →
Recommended fix High confidence

Linux Kernel: upgrade to 4.4.276+/4.9.276+/4.14.240+/4.19.198+/5.13.4+; Debian: apply latest security updates; RHEL 8: apply latest RHSA

  1. 1. Identify the current kernel version using 'uname -r' or 'cat /proc/version'
  2. 2. For Linux Kernel: Upgrade to version 4.4.276 or later, 4.9.276 or later, 4.14.240 or later, 4.19.198 or later, or 5.13.4 or later based on your current branch
  3. 3. For Debian 9 (Stretch) and Debian 10 (Buster): Apply vendor security updates via 'apt update && apt upgrade' to receive the patched kernel
  4. 4. For RHEL/CentOS/Enterprise Linux 8: Apply vendor security updates via 'yum update' or 'dnf update'
  5. 5. For NetApp Solidfire and Element Software: Apply vendor-specific patches as referenced in security.netapp.com advisories
  6. 6. Reboot the system to load the fixed kernel
  7. 7. Verify the fix by checking 'virtio_console.c' includes the length validation check for buf->len against buffer size
Caveat Kernel upgrades may require system reboot and could have compatibility impacts with custom kernel modules; minor kernel version jumps within same major release typically safe

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

We can perform the upgrade in your staging environment and verify nothing breaks — typical engagement from $3,200. Get the upgrade done

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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-2021-38160 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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