SB2026052080 - Ubuntu update for linux
Published: May 20, 2026 Updated: May 22, 2026
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 5 vulnerabilities.
1) Improper control of a resource through its lifetime (CVE-ID: CVE-2026-31431)
CWE-ID: CWE-664 - Improper control of a resource through its lifetime
CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:A/U:Amber
The vulnerability allows a local user to escalate privileges on the system.
The vulnerability exists due to improper memory handling within the authencesn cryptographic template in algif_aead when processing AEAD operations. A local user can trigger the vulnerable code path to execute arbitrary code on the system.
Note, this vulnerability was dubbed "Copy Fail".
2) Out-of-bounds write (CVE-ID: CVE-2026-43078)
CWE-ID: CWE-787 - Out-of-bounds write
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 an out-of-bounds write in af_alg_pull_tsgl when reassigning pages. A local user can trigger page reassignment that reassigns one more page than necessary to cause a denial of service.
3) Improper input validation (CVE-ID: CVE-2026-43077)
CWE-ID: CWE-20 - Improper input validation
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 improper input validation in algif_aead when processing decryption requests. A local user can provide a crafted receive buffer size to cause a denial of service.
4) Always-Incorrect Control Flow Implementation (CVE-ID: CVE-2026-43033)
CWE-ID: CWE-670 - Always-Incorrect Control Flow Implementation
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 improper handling of high-order sequence bits in authencesn when decrypting data out of place. A local user can trigger out-of-place decryption with a specially crafted data layout to cause a denial of service.
5) Use-after-free (CVE-ID: CVE-2026-31504)
CWE-ID: CWE-416 - Use After Free
CVSSv4: CVSS:4.0/AV:L/AC:L/AT:P/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 use-after-free in packet_release() and fanout group handling when processing a concurrent NETDEV_UP event during socket release. A local user can trigger a race condition to cause a denial of service.
The issue affects fanout sockets during a race that can leave a dangling pointer in the fanout array.
Remediation
Install update from vendor's website.