CVE intelligence and bounded remediation

CVE-2019-15791 — Linux Linux Kernel security vulnerability

High CVSS 7.8

In shiftfs, a non-upstream patch to the Linux kernel included in the Ubuntu 5.0 and 5.3 kernel series, shiftfs_btrfs_ioctl_fd_replace() installs an fd referencing a file from the lower filesystem without taking an additional reference to that file. After the btrfs ioctl completes this fd is closed, which then puts a reference to that file, leading to a refcount underflow.

Severity
High
CVSS
7.8 (3.1)
Published
2020-04-24
CISA KEV
Not currently listed
Ecosystem
linux/kernel
Weaknesses
CWE-672, CWE-191

Affected products

  • linux / linux_kernel / 5.0
  • linux / linux_kernel / 5.3
  • canonical / ubuntu_linux / 18.04
  • canonical / ubuntu_linux / 19.04

Matched remediation archetype

Use-after-free, double free, and expired resource use

This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.

Check exposure

  • Trace ownership, references, callbacks, asynchronous tasks, and teardown paths around the affected object or resource.
  • Identify reachable inputs and timing or state transitions that can release the object while references remain.
  • Confirm affected builds, allocators, feature flags, architectures, and process privileges.

Remediate safely

  • Apply the maintained ownership or lifetime fix and rebuild all artifacts containing the affected native code.
  • Use explicit ownership, safe reference management, cancellation and join semantics, and idempotent teardown.
  • Add deterministic lifetime tests plus isolated sanitizer and concurrency coverage for shutdown and error paths.

Authoritative sources

Complete CVE record and remediation plan

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