CVE-2019-15794
Reference counting error in overlayfs/shiftfs error path when used in conjuction with aufs
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- Fix
- Fixed in 5.3.0-24.26, 5.0.0-37.40
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- 1 on Exploit-DB
Summary
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.
Timeline
- Public exploit on Exploit-DB
EDB-47692
- CVE published
- Record last updated
Affected versions
- Ubuntu Linux kernel
From 5.3 kernel · fixed in 5.3.0-24.26; From 5.0 kernel · fixed in 5.0.0-37.40