CVE-2019-15794

Advisory lineage Upstream: 0 Downstream: 5
Modified
Published: 23 Apr 2020, 23:55
Last modified:16 Sept 2024, 19:52

Vulnerability Summary

Overall Risk (default)
medium
39/100
CVSS Score
7.2 HIGH
v2.0 (nvd)
EPSS Score
0.09% LOW
0% probability -0.28%
KEV
Not listed
Ransomware
No reports
Public exploits
1 found
Dark Web
Not detected

Timeline

23 Apr 2020, 23:55
Published
Vulnerability first disclosed
16 Sept 2024, 19:52
Last Modified
Vulnerability information updated

Description

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.

CVSS Metrics

  • v3.1•HIGH•Score: 7.1CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
  • v3.1•MEDIUM•Score: 6.7CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
  • v2.0•HIGH•Score: 7.2AV:L/AC:L/Au:N/C:C/I:C/A:C

EPSS Trends

Current EPSS score: 0.09%• Percentile: 26%

Techniques & Countermeasures

  • CWE-672•Operation on a Resource after Expiration or Release

    The product uses, accesses, or otherwise operates on a resource after that resource has been expired, released, or revoked.

Affected Systems

  • canonical•ubuntu_linux

    18.04 | 19.10

  • linux•linux_kernel

    5.0 | 5.3

  • ubuntu•linux_kernel

    ≥ 5.3 kernel, < 5.3.0-24.26 | ≥ 5.0 kernel, < 5.0.0-37.40

References (4)