SB2021041396 - Ubuntu update for linux

Description

This security bulletin contains information about 3 secuirty vulnerabilities.

1) Null pointer dereference (CVE-ID: CVE-2018-13095)

The vulnerability allows a local attacker to cause DoS condition on the target system.

The vulnerability exists in the xfs_bmap_extents_to_btree() function in the Extended File System (XFS) component, as defined in the source code file fs/xfs/libxfs/xfs_inode_buf.c due to boundary error when mounting XFS filesystems. A local attacker can access the system, mount an XFS filesystem that submits malicious input, trigger a NULL pointer dereference memory error and cause the affected software to terminate abnormally.

2) Use-after-free (CVE-ID: CVE-2021-3347)

The vulnerability allows a local user to elevate privileges on the system.

The vulnerability exists due to a use-after-free error when handling PI futexes. A local user can run a specially crafted program to trigger a use-after-free error and execute arbitrary code with elevated privileges.

3) Use-after-free (CVE-ID: CVE-2021-3348)

The vulnerability allows a local authenticated user to escalate privileges on the system.

The vulnerability exists due to a use-after-free error within the nbd_add_socket in drivers/block/nbd.c. A local authenticated user can trigger a use-after-free error and escalate privileges on the system.

Remediation

Install update from vendor's website.

References

• https://ubuntu.com/security/notices/USN-4907-1