CVE-2019-15794
highpriority · track · 37EPSS 0.012 · 67 %ileexploit · functionalEURUUSEPSS · scored 2026-10-26
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
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 6.3–7.3
weaknesses
The CWE weakness classes this flaw belongs to.
exploits (1)
Public proof-of-concept and weaponised exploit code.
affected products (18)
Products and version ranges known to be affected.
also known as (4)
Other names and identifiers for this entity.
sources
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references (21)
External citations — patches, advisories, analysis.
- https://git.launchpad.net/~ubuntu-kernel/ubuntu/+source/linux/+git/eoan/commit/?id=270d16ae48a4dbf1c7e25e94cc3e38b4bea37635cnnvd
- https://git.launchpad.net/~ubuntu-kernel/ubuntu/+source/linux/+git/eoan/commit/?id=ef81780548d20a786cc77ed4203fca146fd81ce3cnnvd
- https://nvd.nist.gov/vuln/detail/CVE-2019-15794cnnvd
- https://packetstormsecurity.com/files/155526/Ubuntu-Security-Notice-USN-4208-1.htmlcnnvd
- https://packetstormsecurity.com/files/155879/Kernel-Live-Patch-Security-Notice-LSN-0061-1.htmlcnnvd
- https://usn.ubuntu.com/4209-1/cnnvd
- https://usn.ubuntu.com/usn/usn-4208-1cnnvd
- https://usn.ubuntu.com/usn/usn-4209-1cnnvd
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