Critical· 9.8official fix available
CVE-2021-47544
CVE-2021-47544 is a critical Linux kernel vulnerability where improper page fragmentation handling during memory faults could corrupt TCP streams. The fix involves upgrading to kernel version 5.16 or later, which prevents nested page allocations during memory faults.
publishedMay 24, 2024
last modifiedAug 4, 2026
sourcesNVD
severity · cvss
9.8
critical · how bad it is
exploitation · epss
<1%
55th percentile · chance of exploitation in 30 days
(ai-assisted) A model wrote this summary from the official data, so double-check it against the source before you act on it. Read the official advisory →
auto-deletes from the system
counting…on Sep 4, 2026
An official fix is available, so this entry is kept for 30 days and then removed automatically.
01
Who is affected
Linux kernel users (specifically versions 5.16 and earlier)
02
Real-world impact
Could allow attackers to corrupt HTTP traffic via crafted requests, potentially leading to data leaks or service disruption
03
Why this severity
CVSS 9.8 (critical) due to high confidentiality, integrity, and availability impact
04
What to do about it
official fix available
recommended steps
- 011. Upgrade the Linux kernel to version 5.16 or later to apply the fix in commit 20eb4f29b602.
NVD-referenced vulnerability description and commit 20eb4f29b602
05
Timeline
- May 24, 2024 · May 24, 2024PublishedDisclosed and added to the National Vulnerability Database.
- Aug 4, 2026 · 2d agoAdvisory updatedThe NVD record was last revised.
- Aug 5, 2026 · 1d agoOfficial fix availableA vendor patch or mitigation now exists — see the remediation steps above.
06
How it’s attacked
Attack vectorNetwork (remote)
Attack complexityLow
Privileges requiredNone
User interactionNone needed
ScopeUnchanged
Confidentiality impactHigh
Integrity impactHigh
Availability impactHigh
07
References & advisories
(ai-assisted) A model wrote this summary from the official data, so double-check it against the source before you act on it. Read the official advisory →