CVE-2026-45966

In the Linux kernel, the following vulnerability has been resolved: apparmor: fix NULL pointer dereference in __unix_needs_revalidation When receiving file descriptors via SCM_RIGHTS, both the socket pointer and the socket's sk pointer can be NULL during socket setup or teardown, causing NULL pointer dereferences in __unix_needs_revalidation(). This is a regression in AppArmor 5.0.0 (kernel 6.17+) where the new __unix_needs_revalidation() function was added without proper NULL checks. The crash manifests as: BUG: kernel NULL pointer dereference, address: 0x0000000000000018 RIP: aa_file_perm+0xb7/0x3b0 (or +0xbe/0x3b0, +0xc0/0x3e0) Call Trace: apparmor_file_receive+0x42/0x80 security_file_receive+0x2e/0x50 receive_fd+0x1d/0xf0 scm_detach_fds+0xad/0x1c0 The function dereferences sock->sk->sk_family without checking if either sock or sock->sk is NULL first. Add NULL checks for both sock and sock->sk before accessing sk_family.

In the Linux kernel, the following vulnerability has been resolved:

apparmor: fix NULL pointer dereference in __unix_needs_revalidation

When receiving file descriptors via SCM_RIGHTS, both the socket pointer and the socket's sk pointer can be NULL during socket setup or teardown, causing NULL pointer dereferences in __unix_needs_revalidation().

This is a regression in AppArmor 5.0.0 (kernel 6.17+) where the new __unix_needs_revalidation() function was added without proper NULL checks.

The crash manifests as: BUG: kernel NULL pointer dereference, address: 0x0000000000000018 RIP: aa_file_perm+0xb7/0x3b0 (or +0xbe/0x3b0, +0xc0/0x3e0) Call Trace: apparmor_file_receive+0x42/0x80 security_file_receive+0x2e/0x50 receive_fd+0x1d/0xf0 scm_detach_fds+0xad/0x1c0

The function dereferences sock->sk->sk_family without checking if either sock or sock->sk is NULL first.

Add NULL checks for both sock and sock->sk before accessing sk_family.

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,…

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:

• ARM64 architecture;
• S390 architecture;
• Block layer subsystem;
• Cryptographic API;
• DMA engine subsystem;
• GPU drivers;
• InfiniBand drivers;
• Ethernet bonding driver;
• STMicroelectronics network drivers;
• Network drivers;
• NVME drivers;
• SCSI subsystem;
• USB over IP driver;
• File systems infrastructure;
• Ext4 file system;
• Network file system (NFS) server daemon;
• SMB network file system;
• Kernel thread helper (kthread);
• Distributed Switch Architecture;
• IPv6 networking;
• Netfilter;
• Tracing infrastructure;
• Control group (cgroup);
• Kernel exit() syscall;
• Scatterlist API;
• Memory management;
• B.A.T.M.A.N. meshing protocol;
• Ethernet bridge;
• Ceph Core library;
• IPv4 networking;
• MAC80211 subsystem;
• Multipath TCP;
• Packet sockets;
• RxRPC session sockets;
• SMC sockets;
• TLS protocol;
• Unix domain sockets;
• X.25 network layer;
• AppArmor security module; (CVE-2025-71088, CVE-2025-71090, CVE-2025-71127, CVE-2025-71134, CVE-2025-71141, CVE-2025-71142, CVE-2025-71144, CVE-2025-71152, CVE-2025-71155, CVE-2026-22984, CVE-2026-23112, CVE-2026-23231, CVE-2026-23272, CVE-2026-23273, CVE-2026-23274, CVE-2026-23278, CVE-2026-23351, CVE-2026-23392, CVE-2026-23394, CVE-2026-23427, CVE-2026-23428, CVE-2026-23450, CVE-2026-23455, CVE-2026-31402, CVE-2026-31418, CVE-2026-31419, CVE-2026-31436, CVE-2026-31448, CVE-2026-31478, CVE-2026-31504, CVE-2026-31533, CVE-2026-31607, CVE-2026-31635, CVE-2026-31637, CVE-2026-31649, CVE-2026-31657, CVE-2026-31659, CVE-2026-31668, CVE-2026-31669, CVE-2026-31682, CVE-2026-31685, CVE-2026-31718, CVE-2026-43011, CVE-2026-43033, CVE-2026-43037, CVE-2026-43038, CVE-2026-43071, CVE-2026-43077, CVE-2026-43078, CVE-2026-43083, CVE-2026-43114, CVE-2026-43117, CVE-2026-43125, CVE-2026-43186, CVE-2026-43197, CVE-2026-43304, CVE-2026-43341, CVE-2026-43376, CVE-2026-43378, CVE-2026-43383, CVE-2026-43384, CVE-2026-43402, CVE-2026-43406, CVE-2026-43407, CVE-2026-43414, CVE-2026-43493, CVE-2026-43501, CVE-2026-45898, CVE-2026-45966, CVE-2026-45988, CVE-2026-46028, CVE-2026-46039, CVE-2026-46043, CVE-2026-46115, CVE-2026-46119, CVE-2026-46135, CVE-2026-46185, CVE-2026-46195, CVE-2026-46243, CVE-2026-46244, CVE-2026-46266, CVE-2026-46289, CVE-2026-46316, CVE-2026-46325)