Vulnerability in Linux Kernel
CVE-2019-15794
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.
EPSS: 0.012 (64.9th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 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.
Affected products
- Linux Linux_kernel — versions 5.0, 5.3
- Canonical Ubuntu_linux — versions 18.04, 19.10
- Ubuntu Linux Kernel — versions 5.3 kernel, 5.0 kernel
Weakness classification (CWE)
References
- security@ubuntu.com (Patch, Mailing List, Third Party Advisory, x_refsource_MISC)
- security@ubuntu.com (Patch, Mailing List, Third Party Advisory, x_refsource_MISC)
- security@ubuntu.com (Third Party Advisory, x_refsource_MISC)
- security@ubuntu.com (Third Party Advisory, x_refsource_MISC)
Frequently asked questions
- What is CVE-2019-15794?
- CVE-2019-15794 is a high-severity vulnerability in Linux Kernel, classified under Operation on a Resource after Expiration or Release. CVSS score: 7.1/10. Published 2020-04-24.
- How severe is CVE-2019-15794?
- High severity. CVSS v3 base score is 7.1 out of 10.