Use-after-free in Linux kernel

1) Use-after-free

EUVDB-ID: #VU34962

Risk: Medium

CVSSv4.0: 4.6 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2019-19813

CWE-ID: CWE-416 - Use After Free

Exploit availability: No

Description

The vulnerability allows a remote non-authenticated attacker to perform a denial of service (DoS) attack.

In the Linux kernel 5.0.21, mounting a crafted btrfs filesystem image, performing some operations, and then making a syncfs system call can lead to a use-after-free in __mutex_lock in kernel/locking/mutex.c. This is related to mutex_can_spin_on_owner in kernel/locking/mutex.c, __btrfs_qgroup_free_meta in fs/btrfs/qgroup.c, and btrfs_insert_delayed_items in fs/btrfs/delayed-inode.c.

Mitigation

Install update from vendor's website.

Vulnerable software versions

Linux kernel: 5.0.21

CPE2.3

• cpe:2.3:o:linux_foundation:linux_kernel:5.0.21:*:*:*:*:*:*:*

External links

https://github.com/bobfuzzer/CVE/tree/master/CVE-2019-19813
https://security.netapp.com/advisory/ntap-20200103-0001/
https://usn.ubuntu.com/4414-1/

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.