Reference count underflow in shiftfs
41Vexday Risk Score
No sign of exploitation. It has a public proof of concept.
ssvc Attendcvss 7.1epss 1.3%
from disclosure to weapon0 days
Published on NVDApr 23
1st PoCNov 20
exploitation probability
1.3%top 32% of all CVEs
observed exploitation
nono source reports it
1 public exploit(s)
In shiftfs, a non-upstream patch to the Linux kernel included in the Ubuntu 5.0 and 5.3 kernel series, shiftfs_btrfs_ioctl_fd_replace() installs an fd referencing a file from the lower filesystem without taking an additional reference to that file. After the btrfs ioctl completes this fd is closed, which then puts a reference to that file, leading to a refcount underflow.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
Affected products
Ubuntu · Shiftfs in the Linux kernelpublic PoCs found — 1✓ VexDay Proof
exploitdb✓ VexDay Proofwww.exploit-db.com/exploits/47693⚠ Public resources, to assess the exposure of systems you control or are authorized to test. Test only with authorization.