CVE-2019-15794 Detail

Current 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.


View Analysis Description

Severity



CVSS 3.x Severity and Metrics:

NIST CVSS score
NIST: NVD
Base Score:  6.7 MEDIUM
Vector:  CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H

Nist CVSS score does not match with CNA score
CNA:  Canonical Ltd.
Base Score:  7.1 HIGH
Vector:  CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H


NVD Analysts use publicly available information to associate vector strings and CVSS scores. We also display any CVSS information provided within the CVE List from the CNA.

Note: It is possible that the NVD CVSS may not match that of the CNA. The most common reason for this is that publicly available information does not provide sufficient detail or that information simply was not available at the time the CVSS vector string was assigned.

References to Advisories, Solutions, and Tools

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Hyperlink Resource
https://git.launchpad.net/~ubuntu-kernel/ubuntu/+source/linux/+git/eoan/commit/?id=270d16ae48a4dbf1c7e25e94cc3e38b4bea37635 Mailing List  Patch  Third Party Advisory 
https://git.launchpad.net/~ubuntu-kernel/ubuntu/+source/linux/+git/eoan/commit/?id=ef81780548d20a786cc77ed4203fca146fd81ce3 Mailing List  Patch  Third Party Advisory 
https://usn.ubuntu.com/usn/usn-4208-1 Third Party Advisory 
https://usn.ubuntu.com/usn/usn-4209-1 Third Party Advisory 

Weakness Enumeration

CWE-ID CWE Name Source
CWE-672 Operation on a Resource after Expiration or Release cwe source acceptance level NIST   Reference acceptance level Canonical Ltd.  

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Change History

2 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2019-15794
NVD Published Date:
04/23/2020
NVD Last Modified:
05/26/2020
Source:
MITRE