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.
Does this matter?
A public exploit is published in Exploit-DB (verified), so the technical barrier is gone even though the severity is medium and EPSS is 1.2%. Treat it as high on anything reachable from the internet.
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 3.1
- 6.7 MEDIUMCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 1.16% probability · 67th percentile
- Public exploits
- 1 in Exploit-DB · verified · first 20 November 2019
- CISA KEV
- Not listed
- Weakness
- CWE-672
- Affected
- linux/linux kernel · canonical/ubuntu linux
- Source
- security@ubuntu.com
EPSS 1.2% since 27 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
Public exploits (1)
Entries in Exploit-DB that cite this CVE. Links go to the Exploit-DB page and to the file in the public repository; nothing is hosted here. A verified tick means the Exploit-DB team confirmed the exploit works against the stated version.
References
- https://git.launchpad.net/~ubuntu-kernel/ubuntu/+source/linux/+git/eoan/commit/?id=270d16ae48a4dbf1c7e25e94cc3e38b4bea37635Mailing List, Patch, Third Party Advisory
- https://git.launchpad.net/~ubuntu-kernel/ubuntu/+source/linux/+git/eoan/commit/?id=ef81780548d20a786cc77ed4203fca146fd81ce3Mailing List, Patch, Third Party Advisory
- https://usn.ubuntu.com/usn/usn-4208-1Third Party Advisory
- https://usn.ubuntu.com/usn/usn-4209-1Third Party Advisory
- https://git.launchpad.net/~ubuntu-kernel/ubuntu/+source/linux/+git/eoan/commit/?id=270d16ae48a4dbf1c7e25e94cc3e38b4bea37635Mailing List, Patch, Third Party Advisory
- https://git.launchpad.net/~ubuntu-kernel/ubuntu/+source/linux/+git/eoan/commit/?id=ef81780548d20a786cc77ed4203fca146fd81ce3Mailing List, Patch, Third Party Advisory
- https://usn.ubuntu.com/usn/usn-4208-1Third Party Advisory
- https://usn.ubuntu.com/usn/usn-4209-1Third Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.