SB2026060614 - Ubuntu update for linux

Description

This security bulletin contains information about 3 vulnerabilities.

1) Resource management error (CVE-ID: CVE-2026-43284)

CWE-ID: CWE-399 - Resource Management Errors

CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:A/U:Amber

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

The xfrm-ESP Page-Cache Write vulnerability exists due to improper management of internal resources in esp_input() function in net/ipv4/esp4.c and esp6_input() function in net/ipv6/esp6.c. A local user can execute arbitrary code with root privileges. 

Note, this is one of two vulnerabilities reported as Dirty Frag.

2) Resource management error (CVE-ID: CVE-2026-43500)

CWE-ID: CWE-399 - Resource Management Errors

CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:A/U:Amber

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

The RxRPC Page-Cache Write vulnerability exists due to improper management of internal resources. A local user can execute arbitrary code with root privileges.

Note, this vulnerability is one of two issues described as Dirty Frag.

3) Double free (CVE-ID: CVE-2026-43494)

CWE-ID: CWE-415 - Double Free

CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear

The vulnerability allows a local user to cause a denial of service.

The vulnerability exists due to a double free in rds_message_zcopy_from_user() and rds_message_purge() when handling a zerocopy page pin failure during sendmsg processing. A local user can trigger a page pin failure and subsequent cleanup to cause a denial of service.

Remediation

Install update from vendor's website.

References

• https://ubuntu.com/security/notices/USN-8389-1