CVE-2019-11487

Published: 23 April 2019

The Linux kernel before 5.1-rc5 allows page->_refcount reference count overflow, with resultant use-after-free issues, if about 140 GiB of RAM exists. This is related to fs/fuse/dev.c, fs/pipe.c, fs/splice.c, include/linux/mm.h, include/linux/pipe_fs_i.h, kernel/trace/trace.c, mm/gup.c, and mm/hugetlb.c. It can occur with FUSE requests.

From the Ubuntu Security Team

It was discovered that an integer overflow existed in the Linux kernel when reference counting pages, leading to potential use-after-free issues. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code.

Notes

Requires >= 140 GiB of RAM which is rare

Status

Severity score breakdown

References

• https://lwn.net/Articles/786044/
• https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=15fab63e1e57be9fdb5eec1bbc5916e9825e9acb
• https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=6b3a707736301c2128ca85ce85fb13f60b5e350a
• https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=88b1a17dfc3ed7728316478fae0f5ad508f50397
• https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=8fde12ca79aff9b5ba951fce1a2641901b8d8e64
• https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=f958d7b528b1b40c44cfda5eabe2d82760d868c3
• https://ubuntu.com/security/notices/USN-4069-1
• https://ubuntu.com/security/notices/USN-4069-2
• https://ubuntu.com/security/notices/USN-4115-1
• https://ubuntu.com/security/notices/USN-4118-1
• https://ubuntu.com/security/notices/USN-4145-1
• https://www.cve.org/CVERecord?id=CVE-2019-11487
• NVD
• Launchpad
• Debian

Bugs

• https://bugs.chromium.org/p/project-zero/issues/detail?id=1752