SB2021072084 - Ubuntu update for linux-oem-5.10
Published: July 20, 2021
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 4 secuirty vulnerabilities.
1) Integer overflow (CVE-ID: CVE-2021-33909)
The vulnerability allows a local user to escalate privileges on the system.
The vulnerability exists due to integer overflow during size_t-to-int conversion when creating, mounting, and deleting a deep directory structure whose total path length exceeds 1GB. An unprivileged local user can write up to 10-byte string to an offset of exactly -2GB-10B below the beginning of a vmalloc()ated kernel buffer.
Successful exploitation of vulnerability may allow an attacker to exploit the our-of-bounds write vulnerability to execute arbitrary code with root privileges.
2) Use after free (CVE-ID: CVE-2021-28691)
The vulnerability allows a local user to execute arbitrary code.
Guest triggered use-after-free in Linux xen-netback A malicious or buggy network PV frontend can force Linux netback to disable the interface and terminate the receive kernel thread associated with queue 0 in response to the frontend sending a malformed packet. Such kernel thread termination will lead to a use-after-free in Linux netback when the backend is destroyed, as the kernel thread associated with queue 0 will have already exited and thus the call to kthread_stop will be performed against a stale pointer.
3) Double Free (CVE-ID: CVE-2021-3564)
The vulnerability allows a local attacker to perform a denial of service attack.
The vulnerability exists due to bluetooth subsystem in the Linux kernel does not properly handle HCI device detach events. An attacker with physical access to the system can trigger double free error and perform a denial of service attack.
4) Use-after-free (CVE-ID: CVE-2021-3573)
The vulnerability allows local user to escalate their privileges on the system.
The vulnerability exists due to a use-after-free in hci_sock_bound_ioctl() function of the Linux kernel HCI subsystem triggers race condition of the call hci_unregister_dev() together with one of the calls hci_sock_blacklist_add(), hci_sock_blacklist_del(), hci_get_conn_info(), hci_get_auth_info(). A privileged local user can use this flaw to crash the system or escalate privileges on the system.
Remediation
Install update from vendor's website.