USN-8374-1: Linux kernel vulnerabilities

It was discovered that the Linux kernel algif_aead module did not properly
handle in-place cryptographic operations. This flaw is known as Copy Fail.
A local attacker could use this to escalate privileges, or possibly escape
a container. (CVE-2026-31431)

It was discovered that the Linux kernel did not properly handle shared page
fragments during socket buffer operations, collectively known as Dirty
Frag. A logic flaw existed in the XFRM ESP-in-TCP subsystem and in the
RxRPC networking subsystem when processing paged fragments. A local
attacker could use this to escalate privileges, or possibly escape a
container. (CVE-2026-43284, CVE-2026-43500, CVE-2026-45998, CVE-2026-46000)

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,
CVE-2026-46300)

Qualys discovered that a race condition existed in the ptrace subsystem of
the Linux kernel when privileged processes are exiting. An unprivileged
local attacker could use this issue to expose sensitive information.
(CVE-2026-46333)

Tristan Madani discovered that Ubuntu Linux kernel 6.8, 6.17 and 7.0
contain a memory leak when handling AppArmor notifications. A local
attacker could use this to cause resource exhaustion. (CVE-2026-47326)

Tristan Madani discovered that Ubuntu Linux kernel 6.8, 6.17 and 7.0
contain a NULL pointer dereference when handling AppArmor notifications. A
local attacker could use this to cause a kernel oops. (CVE-2026-47327)

Tristan Madani discovered that Ubuntu Linux kernel 6.8, 6.17 and 7.0
contained an invalid free when handling AppArmor notifications. A local
attacker could use this to corrupt kernel memory. (CVE-2026-47328)

Tristan Madani discovered that Ubuntu Linux kernel 6.8, 6.17 and 7.0
contained insufficient validation of AppArmor notification responses. A
local attacker could use this to allow crafted responses to be processed.
(CVE-2026-47329)

Tristan Madani discovered that Ubuntu Linux kernel 6.8, 6.17 and 7.0 used
an uninitialized variable when handling AppArmor notifications. A local
attacker could use this to cause incorrect caching of data.
(CVE-2026-47330)

Tristan Madani discovered that Ubuntu Linux kernel 6.8, 6.17 and 7.0
contained an out-of-bounds (OOB) read when handling AppArmor notifications.
A local attacker could use this to cause information disclosure of kernel
memory. (CVE-2026-47332)

Tristan Madani discovered that Ubuntu Linux kernel 6.8, 6.17 and 7.0
contained a out-of-bounds (OOB) read when handling AppArmor notifications.
A local attacker could use this to cause kernel memory corruption and,
theoretically, influence processing of AppArmor policies. (CVE-2026-47333)

Tristan Madani discovered that Ubuntu Linux kernel 6.8, 6.17 and 7.0
contained incorrect holding of locks when handling AppArmor notifications.
A local attacker could use this to cause a kernel panic or deadlock.
(CVE-2026-47334)

Tristan Madani and Trevor Lawrence have each independently discovered that
Ubuntu Linux kernel 6.8, 6.17 and 7.0 contained a NULL pointer dereference
when handling AppArmor network socket mediation. A local attacker could use
this to cause a kernel oops. (CVE-2026-47337)

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:
- S390 architecture;
- Cryptographic API;
- GPU drivers;
- Ethernet bonding driver;
- Network file system (NFS) server daemon;
- Distributed Switch Architecture;
- Netfilter;
- Control group (cgroup);
- Kernel kexec() syscall;
- Memory management;
- MAC80211 subsystem;
- Multipath TCP;
- Packet sockets;
- RDS protocol;
- RxRPC session sockets;
- TLS protocol;
- Unix domain sockets;
- AppArmor security module;
(CVE-2025-71088, CVE-2025-71090, CVE-2025-71127, CVE-2025-71134,
CVE-2025-71139, CVE-2025-71141, CVE-2025-71142, CVE-2025-71144,
CVE-2025-71152, CVE-2025-71155, CVE-2026-23274, CVE-2026-23351,
CVE-2026-23394, CVE-2026-31419, CVE-2026-31504, CVE-2026-31533,
CVE-2026-31676, CVE-2026-43033, CVE-2026-43077, CVE-2026-43078,
CVE-2026-43494, CVE-2026-45966, CVE-2026-46028)