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Linux KernelOperating system · Linux

CVE-2021-3600

HIGH · 7.8 CVSS v3.1 Published 2024-01-08
Fix available
A fix is available. Upgrade to 4.14.308 / 4.19.206 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
It was discovered that the eBPF implementation in the Linux kernel did not properly track bounds information for 32 bit registers when performing div and mod operations. A local attacker could use this to possibly execute arbitrary code.

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-125

The code reads past the end (or before the start) of a buffer, returning memory that was never meant to be exposed. Attackers use it to leak secrets like keys or to defeat memory-protection defences. Remediation is validating indices and lengths before every read.

General guidance for the out-of-bounds read 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:>= 4.14.115, < 4.14.308>= 4.15, < 4.19.206>= 4.20, < 5.4.98>= 5.5, < 5.10.16= 5.11
Ubuntu LinuxOperating system
Affected:= 14.04= 16.04= 18.04
FedoraOperating system
Affected:= 34
Enterprise LinuxOperating system
Affected:= 8.0

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 4.14.308 / 4.19.206 / 5.4.98 or later
Fixed in 4.14.3084.19.2065.4.98
Vendor patch git.kernel.org →
Recommended fix High confidence

Upgrade to Linux kernel 4.14.308+, 4.19.206+, 5.4.98+, 5.10.16+, or a later stable release. For Ubuntu: upgrade to a HWE kernel receiving fixes. For RHEL/EL8: upgrade to the latest kernel from the 8.x stream.

  1. 1. Identify the currently running kernel version: uname -r
  2. 2. For Ubuntu systems: Run 'sudo apt update && sudo apt upgrade' to install the latest kernel security updates, or manually install a fixed kernel package (linux-image-<version>) from Ubuntu security notices
  3. 3. For RHEL/CentOS/Enterprise Linux 8: Run 'sudo dnf update kernel' to apply the fixed kernel version
  4. 4. For Fedora 34: Run 'sudo dnf update kernel' to apply the fixed kernel version
  5. 5. For other distributions using upstream kernel: Rebuild kernel with commit e88b2c6e5a4d9ce30d75391e4d950da74bb2bd90 applied, or upgrade to a stable release containing this fix
  6. 6. After kernel installation/update, reboot the system to load the fixed kernel: sudo systemctl reboot
  7. 7. Verify the fix is applied by checking the kernel version after reboot matches a version >= 4.14.308, 4.19.206, 5.4.98, or 5.10.16 as appropriate
Caveat Kernel upgrades may introduce regressions with proprietary drivers or specific hardware configurations; test in non-production environment first before deploying to production systems.

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-2021-3600 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