SB2023100562 - Ubuntu update for linux
Published: October 5, 2023 Updated: January 4, 2026
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 6 secuirty vulnerabilities.
1) Race condition (CVE-ID: CVE-2021-4001)
The vulnerability allows a local user to escalate privileges on the system.
The vulnerability exists due to a race condition in kernel/bpf/syscall.c in Linux kernel ebpf. A local user can exploit the race between bpf_map_update_elem and bpf_map_freeze and modify the frozen mapped address space.
2) Resource exhaustion (CVE-ID: CVE-2023-1206)
The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.
The vulnerability exists due to a hash collision flaw in the IPv6 connection lookup table in the Linux kernel’s IPv6 functionality when an attacker makes a new kind of SYN flood attack. A remote attacker can increase the CPU usage of the server that accepts IPV6 connections up to 95%.
3) NULL pointer dereference (CVE-ID: CVE-2023-3212)
The vulnerability allows a local user to perform a denial of service (DoS) attack.
The vulnerability exists due to a NULL pointer dereference error within the gfs2 file system in the Linux kernel. A local user can perform a denial of service (DoS) attack.
4) NULL pointer dereference (CVE-ID: CVE-2023-3338)
The vulnerability allows a local user to perform a denial of service (DoS) attack.
The vulnerability exists due to a NULL pointer dereference error within the DECnet socket in net/decnet/dn_nsp_out.c. A local user can trigger a NULL pointer dereference and perform a denial of service (DoS) attack.
5) Use-after-free (CVE-ID: CVE-2023-3863)
The vulnerability allows a local user to escalate privileges on the system.
The vulnerability exists due to a use-after-free error within the nfc_llcp_find_local() function in net/nfc/llcp_core.c in NFC implementation in Linux kernel. A local user can execute arbitrary code with elevated privileges.
6) Type Confusion (CVE-ID: CVE-2023-4194)
The vulnerability allows a local user to bypass implemented security restrictions.
The vulnerability exists due to a type confusion error in TUN/TAP functionality. A local user can bypass network filters and gain unauthorized access to some resources.
The vulnerability exists due to incomplete fix for #VU72742 (CVE-2023-1076).
Remediation
Install update from vendor's website.