{"id":"CVE-2019-15794","details":"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-\u003evm_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.","modified":"2026-03-12T23:01:26.116545Z","published":"2020-04-24T00:15:11.933Z","references":[{"type":"ADVISORY","url":"https://usn.ubuntu.com/usn/usn-4208-1"},{"type":"ADVISORY","url":"https://usn.ubuntu.com/usn/usn-4209-1"},{"type":"FIX","url":"https://git.launchpad.net/~ubuntu-kernel/ubuntu/+source/linux/+git/eoan/commit/?id=ef81780548d20a786cc77ed4203fca146fd81ce3"},{"type":"FIX","url":"https://git.launchpad.net/~ubuntu-kernel/ubuntu/+source/linux/+git/eoan/commit/?id=270d16ae48a4dbf1c7e25e94cc3e38b4bea37635"}],"affected":[{"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2019-15794.json","unresolved_ranges":[{"events":[{"introduced":"0"},{"last_affected":"5.0"}]},{"events":[{"introduced":"0"},{"last_affected":"5.3"}]},{"events":[{"introduced":"0"},{"last_affected":"18.04"}]},{"events":[{"introduced":"0"},{"last_affected":"19.10"}]}]}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H"}]}