USN-8529-1: Linux kernel vulnerabilities

Q: Who is realistically exposed to the Fragnesia flaw?

Systems running an affected Linux kernel are exposed when a local attacker can execute code on the host. Containerized environments may also be at risk because the flaw could possibly allow a container escape.

Q: What access does an attacker need to exploit the specifically described privilege-escalation issue?

The description identifies the attacker as local. It does not state that remote network access alone is sufficient for exploiting this flaw.

Q: Which kernel areas are covered by this update besides the ESP-in-TCP issue?

The update addresses issues in InfiniBand, SCSI, thermal drivers, USB over IP, NFS, SMB, tracing, B.A.T.M.A.N., Ethernet bridging, Ceph, DCCP, IPv4, IPv6, Netfilter, RxRPC, and X.25. The description also states that some of these issues could allow an attacker to compromise the system.

Published Jul 10, 2026

Updated

It was discovered that a logic flaw existed in the XFRM ESP-in-TCP subsystem in the Linux kernel when handling socket buffer fragments. This flaw is known as Fragnesia. A local attacker could use this to escalate privileges, or possibly escape a container. (CVE-2026-43503)

Several security issues were discovered in the Linux kernel. An attacker could possibly use these to compromise the system. This update corrects flaws in the following subsystems: - InfiniBand drivers; - SCSI subsystem; - Thermal drivers; - USB over IP driver; - Network file system (NFS) server daemon; - SMB network file system; - Tracing infrastructure; - B.A.T.M.A.N. meshing protocol; - Ethernet bridge; - Ceph Core library; - DCCP (Datagram Congestion Control Protocol); - IPv4 networking; - IPv6 networking; - Netfilter; - RxRPC session sockets; - X.25 network layer; (CVE-2021-47202, CVE-2024-56643, CVE-2026-23272, CVE-2026-23455, CVE-2026-31402, CVE-2026-31607, CVE-2026-31637, CVE-2026-31659, CVE-2026-31682, CVE-2026-31685, CVE-2026-43011, CVE-2026-43037, CVE-2026-43038, CVE-2026-43383, CVE-2026-43407, CVE-2026-43414, CVE-2026-45988, CVE-2026-46043, CVE-2026-46119, CVE-2026-46243)

Affected Software

57 affected componentsFixes available

Linux Linux kernel

All of the following

ubuntu/linux-image-4.15.0-1149-fips<FIPS-140

FIPS-140

Ubuntu Ubuntu=18.04

All of the following

ubuntu/linux-image-4.15.0-1156-oracle<Ubuntu Pro

Ubuntu Pro

Ubuntu Ubuntu=18.04

All of the following

ubuntu/linux-image-4.15.0-1176-kvm<Ubuntu Pro

Ubuntu Pro

Ubuntu Ubuntu=18.04

All of the following

ubuntu/linux-image-4.15.0-1187-gcp<Ubuntu Pro

Ubuntu Pro

Ubuntu Ubuntu=18.04

All of the following

ubuntu/linux-image-4.15.0-1204-azure<Ubuntu Pro

Ubuntu Pro

Ubuntu Ubuntu=18.04

All of the following

ubuntu/linux-image-4.15.0-2095-gcp-fips<FIPS-140

FIPS-140

Ubuntu Ubuntu=18.04

All of the following

ubuntu/linux-image-4.15.0-2112-azure-fips<FIPS-140

FIPS-140

Ubuntu Ubuntu=18.04

All of the following

ubuntu/linux-image-4.15.0-253-generic<Ubuntu Pro

Ubuntu Pro

Ubuntu Ubuntu=18.04

All of the following

ubuntu/linux-image-4.15.0-253-lowlatency<Ubuntu Pro

Ubuntu Pro

Ubuntu Ubuntu=18.04

All of the following

ubuntu/linux-image-azure-4.15<Ubuntu Pro

Ubuntu Pro

Ubuntu Ubuntu=18.04

All of the following

ubuntu/linux-image-azure-fips<FIPS-140

FIPS-140

Ubuntu Ubuntu=18.04

All of the following

ubuntu/linux-image-azure-fips-4.15<FIPS-140

FIPS-140

Ubuntu Ubuntu=18.04

All of the following

ubuntu/linux-image-azure-lts-18.04<Ubuntu Pro

Ubuntu Pro

Ubuntu Ubuntu=18.04

All of the following

ubuntu/linux-image-fips<FIPS-140

FIPS-140

Ubuntu Ubuntu=18.04

All of the following

ubuntu/linux-image-gcp-4.15<Ubuntu Pro

Ubuntu Pro

Ubuntu Ubuntu=18.04

All of the following

ubuntu/linux-image-gcp-fips<FIPS-140

FIPS-140

Ubuntu Ubuntu=18.04

All of the following

ubuntu/linux-image-gcp-fips-4.15<FIPS-140

FIPS-140

Ubuntu Ubuntu=18.04

All of the following

ubuntu/linux-image-gcp-lts-18.04<Ubuntu Pro

Ubuntu Pro

Ubuntu Ubuntu=18.04

All of the following

ubuntu/linux-image-generic<Ubuntu Pro

Ubuntu Pro

Ubuntu Ubuntu=18.04

All of the following

ubuntu/linux-image-kvm<Ubuntu Pro

Ubuntu Pro

Ubuntu Ubuntu=18.04

All of the following

ubuntu/linux-image-lowlatency<Ubuntu Pro

Ubuntu Pro

Ubuntu Ubuntu=18.04

All of the following

ubuntu/linux-image-oracle-4.15<Ubuntu Pro

Ubuntu Pro

Ubuntu Ubuntu=18.04

All of the following

ubuntu/linux-image-oracle-lts-18.04<Ubuntu Pro

Ubuntu Pro

Ubuntu Ubuntu=18.04

All of the following

ubuntu/linux-image-virtual<Ubuntu Pro

Ubuntu Pro

Ubuntu Ubuntu=18.04

ubuntu/linux<4.15.0-253.265

4.15.0-253.265

ubuntu/linux-azure-4.15<4.15.0-1204.219

4.15.0-1204.219

ubuntu/linux-gcp-4.15<4.15.0-1187.204

4.15.0-1187.204

ubuntu/linux-kvm<4.15.0-1176.181

4.15.0-1176.181

ubuntu/linux-oracle<4.15.0-1156.167

4.15.0-1156.167

ubuntu/linux-azure-fips<4.15.0-2112.118

4.15.0-2112.118

ubuntu/linux-fips<4.15.0-1149.161

4.15.0-1149.161

ubuntu/linux-gcp-fips<4.15.0-2095.101

4.15.0-2095.101

Remediation

Recommended actions to resolve this vulnerability, in priority order.

Upgrade
Upgrade ubuntu/linux-image-4.15.0-1149-fips to a version that resolves this vulnerability.
Fixed in FIPS-140
Upgrade
Upgrade ubuntu/linux-image-4.15.0-1156-oracle to a version that resolves this vulnerability.
Fixed in Ubuntu Pro
Upgrade
Upgrade ubuntu/linux-image-4.15.0-1176-kvm to a version that resolves this vulnerability.
Fixed in Ubuntu Pro
Upgrade
Upgrade ubuntu/linux-image-4.15.0-1187-gcp to a version that resolves this vulnerability.
Fixed in Ubuntu Pro
Upgrade
Upgrade ubuntu/linux-image-4.15.0-1204-azure to a version that resolves this vulnerability.
Fixed in Ubuntu Pro
Upgrade
Upgrade ubuntu/linux-image-4.15.0-2095-gcp-fips to a version that resolves this vulnerability.
Fixed in FIPS-140
Upgrade
Upgrade ubuntu/linux-image-4.15.0-2112-azure-fips to a version that resolves this vulnerability.
Fixed in FIPS-140
Upgrade
Upgrade ubuntu/linux-image-4.15.0-253-generic to a version that resolves this vulnerability.
Fixed in Ubuntu Pro
Upgrade
Upgrade ubuntu/linux-image-4.15.0-253-lowlatency to a version that resolves this vulnerability.
Fixed in Ubuntu Pro
Upgrade
Upgrade ubuntu/linux-image-azure-4.15 to a version that resolves this vulnerability.
Fixed in Ubuntu Pro
Upgrade
Upgrade ubuntu/linux-image-azure-fips to a version that resolves this vulnerability.
Fixed in FIPS-140
Upgrade
Upgrade ubuntu/linux-image-azure-fips-4.15 to a version that resolves this vulnerability.
Fixed in FIPS-140
Upgrade
Upgrade ubuntu/linux-image-azure-lts-18.04 to a version that resolves this vulnerability.
Fixed in Ubuntu Pro
Upgrade
Upgrade ubuntu/linux-image-fips to a version that resolves this vulnerability.
Fixed in FIPS-140
Upgrade
Upgrade ubuntu/linux-image-gcp-4.15 to a version that resolves this vulnerability.
Fixed in Ubuntu Pro
Upgrade
Upgrade ubuntu/linux-image-gcp-fips to a version that resolves this vulnerability.
Fixed in FIPS-140
Upgrade
Upgrade ubuntu/linux-image-gcp-fips-4.15 to a version that resolves this vulnerability.
Fixed in FIPS-140
Upgrade
Upgrade ubuntu/linux-image-gcp-lts-18.04 to a version that resolves this vulnerability.
Fixed in Ubuntu Pro
Upgrade
Upgrade ubuntu/linux-image-generic to a version that resolves this vulnerability.
Fixed in Ubuntu Pro
Upgrade
Upgrade ubuntu/linux-image-kvm to a version that resolves this vulnerability.
Fixed in Ubuntu Pro
Upgrade
Upgrade ubuntu/linux-image-lowlatency to a version that resolves this vulnerability.
Fixed in Ubuntu Pro
Upgrade
Upgrade ubuntu/linux-image-oracle-4.15 to a version that resolves this vulnerability.
Fixed in Ubuntu Pro
Upgrade
Upgrade ubuntu/linux-image-oracle-lts-18.04 to a version that resolves this vulnerability.
Fixed in Ubuntu Pro
Upgrade
Upgrade ubuntu/linux-image-virtual to a version that resolves this vulnerability.
Fixed in Ubuntu Pro
Upgrade
Upgrade ubuntu/linux to a version that resolves this vulnerability.
Fixed in 4.15.0-253.265
Upgrade
Upgrade ubuntu/linux-azure-4.15 to a version that resolves this vulnerability.
Fixed in 4.15.0-1204.219
Upgrade
Upgrade ubuntu/linux-gcp-4.15 to a version that resolves this vulnerability.
Fixed in 4.15.0-1187.204
Upgrade
Upgrade ubuntu/linux-kvm to a version that resolves this vulnerability.
Fixed in 4.15.0-1176.181
Upgrade
Upgrade ubuntu/linux-oracle to a version that resolves this vulnerability.
Fixed in 4.15.0-1156.167
Upgrade
Upgrade ubuntu/linux-azure-fips to a version that resolves this vulnerability.
Fixed in 4.15.0-2112.118
Upgrade
Upgrade ubuntu/linux-fips to a version that resolves this vulnerability.
Fixed in 4.15.0-1149.161
Upgrade
Upgrade ubuntu/linux-gcp-fips to a version that resolves this vulnerability.
Fixed in 4.15.0-2095.101
Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Patch USN-8529-1

Event History

Jul 10, 2026

Advisory Published

via Ubuntu·12:00 AM

Data Sourced

via Ubuntu·12:00 AM

DescriptionAffected Software

Advisory Published

via OSV·10:00 AM

Data Sourced

via OSV·10:00 AM

DescriptionAffected Software

Frequently Asked Questions

Who is realistically exposed to the Fragnesia flaw?

Systems running an affected Linux kernel are exposed when a local attacker can execute code on the host. Containerized environments may also be at risk because the flaw could possibly allow a container escape.

What access does an attacker need to exploit the specifically described privilege-escalation issue?

The description identifies the attacker as local. It does not state that remote network access alone is sufficient for exploiting this flaw.

Which kernel areas are covered by this update besides the ESP-in-TCP issue?

The update addresses issues in InfiniBand, SCSI, thermal drivers, USB over IP, NFS, SMB, tracing, B.A.T.M.A.N., Ethernet bridging, Ceph, DCCP, IPv4, IPv6, Netfilter, RxRPC, and X.25. The description also states that some of these issues could allow an attacker to compromise the system.

USN-8529-1: Linux kernel vulnerabilities

Affected Software

Remediation

Event History

Child vulnerabilities

Frequently Asked Questions

Who is realistically exposed to the Fragnesia flaw?

What access does an attacker need to exploit the specifically described privilege-escalation issue?

Which kernel areas are covered by this update besides the ESP-in-TCP issue?

Company

Resources

Contact

Frequently Asked Questions

Who is realistically exposed to the Fragnesia flaw?

What access does an attacker need to exploit the specifically described privilege-escalation issue?

Which kernel areas are covered by this update besides the ESP-in-TCP issue?