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CVE Record

CVE-2019-19816: In the Linux kernel 5.0.21, mounting a crafted btrfs filesystem image and performing some operations can ca...

In the Linux kernel 5.0.21, mounting a crafted btrfs filesystem image and performing some operations can cause slab-out-of-bounds write access in __btrfs_map_block in fs/btrfs/volumes.c, because a value of 1 for the number of data stripes is mishandled.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

This is a Linux kernel Btrfs flaw triggered by mounting a specially crafted filesystem image and then performing operations on it. The sources do not show active exploitation or a CVSS score. Business risk is highest where untrusted disk images, removable media, or tenant-controlled storage images can be mounted.

Executive priority

Treat as a targeted infrastructure hardening issue, not an internet-wide emergency based on current evidence. Prioritize patching where systems mount untrusted Btrfs media or images, and fold remaining hosts into normal kernel security update cycles.

Technical view

CVE-2019-19816 is a slab out-of-bounds write in __btrfs_map_block in fs/btrfs/volumes.c. The issue is described in Linux kernel 5.0.21, where a data-stripe count of 1 is mishandled during Btrfs block mapping after a crafted filesystem image is mounted.

Likely exposure

Exposure is mainly Linux systems that mount Btrfs filesystems from untrusted or user-supplied images. The bundle specifically names Linux kernel 5.0.21; Ubuntu, Debian LTS, and NetApp advisories indicate downstream handling. Network-only exposure is not evidenced in the provided sources.

Exploitation context

The CVE is not listed as KEV, and the provided sources do not claim active exploitation. A public researcher repository is referenced, suggesting public technical details exist, but the bundle does not establish real-world exploitation or remote attackability.

Researcher notes

Evidence is limited to the CVE description and vendor advisory references. The source bundle does not provide CVSS, CWE, exact affected distributions, fixed versions, or exploit-in-the-wild confirmation. Validate impact through vendor kernel package metadata, not kernel version strings alone.

Mitigation direction

  • Apply vendor kernel security updates that include CVE-2019-19816 where applicable.
  • Review Ubuntu, Debian, NetApp, and platform vendor guidance for affected package status.
  • Avoid mounting untrusted Btrfs images on production or privileged systems.
  • Limit mount privileges and removable-media handling to trusted administrators.
  • Prioritize systems processing third-party disk images or tenant-controlled storage artifacts.

Validation and detection

  • Inventory Linux kernels and appliances that support or mount Btrfs.
  • Check whether deployed kernel packages include vendor fixes for CVE-2019-19816.
  • Review workflows that mount user-supplied filesystem images or removable media.
  • Confirm mount permissions are restricted to authorized administrative roles.
  • Monitor vendor advisories for product-specific affected versions and fixes.
Prepared
Confidence
medium
Sources
8

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

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

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CVE-2019-19816 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.