SB2020042446 - Operation on a resource after expiration or release in Linux kernel

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Main Vulnerability Database SB2020042446

SB2020042446 - Operation on a resource after expiration or release in Linux kernel

Published: April 24, 2020 Updated: June 20, 2024

Security Bulletin ID SB2020042446
CSH Severity
Low
Patch available
YES
Number of vulnerabilities 1
Exploitation vector Local access
Highest impact Code execution

Breakdown by Severity

Low 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 1 vulnerability.


1) Operation on a resource after expiration or release (CVE-ID: CVE-2019-15794)

CWE-ID: CWE-672 - Operation on a Resource after Expiration or Release

CVSSv4: 8.4 [CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]


The vulnerability allows a local privileged user to execute arbitrary code.

Overlayfs in the Linux kernel and shiftfs, a non-upstream patch to the Linux kernel included in the Ubuntu 5.0 and 5.3 kernel series, both replace vma->vm_file in their mmap handlers. On error the original value is not restored, and the reference is put for the file to which vm_file points. On upstream kernels this is not an issue, as no callers dereference vm_file following after call_mmap() returns an error. However, the aufs patchs change mmap_region() to replace the fput() using a local variable with vma_fput(), which will fput() vm_file, leading to a refcount underflow.


Remediation

Install update from vendor's website.

References