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CVE Record

CVE-2019-19922: kernel/sched/fair.c in the Linux kernel before 5.3.9, when cpu.cfs_quota_us is used (e.g., with Kubernetes)...

kernel/sched/fair.c in the Linux kernel before 5.3.9, when cpu.cfs_quota_us is used (e.g., with Kubernetes), allows attackers to cause a denial of service against non-cpu-bound applications by generating a workload that triggers unwanted slice expiration, aka CID-de53fd7aedb1. (In other words, although this slice expiration would typically be seen with benign workloads, it is possible that an attacker could calculate how many stray requests are required to force an entire Kubernetes cluster into a low-performance state caused by slice expiration, and ensure that a DDoS attack sent that number of stray requests. An attack does not affect the stability of the kernel; it only causes mismanagement of application execution.)

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

CVE-2019-19922 is a Linux kernel scheduling flaw that can make applications run much slower when CPU quotas are used, such as in Kubernetes. It is a denial-of-service risk through performance collapse, not a kernel crash or takeover. The available sources do not show active exploitation or a CVSS score.

Executive priority

Treat this as a targeted availability risk for Kubernetes and quota-managed Linux platforms. It is not presented as code execution, but it can degrade service performance at cluster scale. Patch through normal kernel maintenance with priority for production clusters using CPU limits.

Technical view

The issue is in kernel/sched/fair.c before Linux 5.3.9. With cpu.cfs_quota_us enabled, scheduler slice expiration can be triggered in a way that mismanages application execution for non-CPU-bound workloads. The referenced fix is Linux commit de53fd7aedb1, included in the 5.3.9 changelog and vendor security updates.

Likely exposure

Most relevant exposure is containerized or quota-managed Linux environments, especially Kubernetes clusters using CPU limits backed by CFS quotas. Systems not using cpu.cfs_quota_us are less directly exposed based on the CVE description.

Exploitation context

The source bundle describes a calculated workload or DDoS pattern that could push a Kubernetes cluster into a low-performance state. CISA KEV is false, and no cited source in the bundle confirms active exploitation.

Researcher notes

Evidence is strongest for the upstream kernel fix and the condition involving CFS CPU quotas. Severity metadata is incomplete in the supplied bundle. Avoid assuming universal Linux exposure; validate both kernel lineage and whether CPU quota enforcement is actually in use.

Mitigation direction

  • Upgrade affected Linux kernels using vendor security updates or a kernel containing commit de53fd7aedb1.
  • Prioritize Kubernetes nodes and other hosts using CFS CPU quotas.
  • Review Ubuntu, Debian, Oracle, NetApp, and kernel advisories for supported package fixes.
  • If patching is delayed, check vendor guidance for safe operational mitigations.
  • Monitor latency, throttling, and saturation symptoms on quota-managed workloads.

Validation and detection

  • Inventory Linux kernel versions and flag systems older than 5.3.9 or unfixed vendor builds.
  • Identify Kubernetes workloads or hosts using cpu.cfs_quota_us through CPU limits.
  • Confirm installed vendor kernel packages include the referenced scheduler fix.
  • Review application performance metrics for unexplained latency under quota-managed workloads.
  • Track remediation completion separately for cluster nodes, appliances, and cloud images.
Prepared
Confidence
high
Sources
9

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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Container behavior lookup

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CVE-2019-19922 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
10Source 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

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