CVE-2025-40078

bpf: Explicitly check accesses to bpf_sock_addr

9.1 CriticalFix available

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

bpf: Explicitly check accesses to bpf_sock_addr

Syzkaller found a kernel warning on the following sock_addr program:

0: r0 = 0
1: r2 = *(u32 *)(r1 +60)
2: exit

which triggers:

verifier bug: error during ctx access conversion (0)

This is happening because offset 60 in bpf_sock_addr corresponds to an implicit padding of 4 bytes, right after msg_src_ip4. Access to this padding isn't rejected in sock_addr_is_valid_access and it thus later fails to convert the access.

This patch fixes it by explicitly checking the various fields of bpf_sock_addr in sock_addr_is_valid_access.

I checked the other ctx structures and is_valid_access functions and didn't find any other similar cases. Other cases of (properly handled) padding are covered in new tests in a subsequent patch.

Attack profile

How easy it is to exploit

Attack vector: Network
Complexity: Low
Privileges needed: None
User interaction: None

What an attacker can affect

Confidentiality: High
Integrity: None
Availability: High

Exploit likelihood

0.24%Up 0.2 points since Oct 28, 2025

What each source reports

OSV Score usedOESA-2026-2417 9.1

kernel security update

The Linux Kernel, the operating system core itself.

Security Fix(es):

In the Linux kernel, the following vulnerability has been resolved:mm/mempolicy: fix migrate_to_node() assuming there is at least one VMA in a MMWe currently assume that there is at least one VMA in a MM, which isn ttrue.So we might end up having find_vma() return NULL, to then de-referenceNULL. So properly handle find_vma() returning NULL.This fixes the report:Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN PTIKASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]CPU: 1 UID: 0 PID: 6021 Comm: syz-executor284 Not tainted 6.12.0-rc7-syzkaller-00187-gf868cd251776 #0Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/30/2024RIP: 0010:migrate_to_node mm/mempolicy.c:1090 [inline]RIP: 0010:do_migrate_pages+0x403/0x6f0 mm/mempolicy.c:1194Code: ...RSP: 0018:ffffc9000375fd08 EFLAGS: 00010246RAX: 0000000000000000 RBX: ffffc9000375fd78 RCX: 0000000000000000RDX: ffff88807e171300 RSI: dffffc0000000000 RDI: ffff88803390c044RBP: ffff88807e171428 R08: 0000000000000014 R09: fffffbfff2039ef1R10: ffffffff901cf78f R11: 0000000000000000 R12: 0000000000000003R13: ffffc9000375fe90 R14: ffffc9000375fe98 R15: ffffc9000375fdf8FS: 00005555919e1380(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033CR2: 00005555919e1ca8 CR3: 000000007f12a000 CR4: 00000000003526f0DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400Call Trace: <TASK> kernel_migrate_pages+0x5b2/0x750 mm/mempolicy.c:1709 __do_sys_migrate_pages mm/mempolicy.c:1727 [inline] __se_sys_migrate_pages mm/mempolicy.c:1723 [inline] __x64_sys_migrate_pages+0x96/0x100 mm/mempolicy.c:1723 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f[email protected]: add unlikely()

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

PCI/MSI: Handle lack of irqdomain gracefully

Alexandre observed a warning emitted from pci_msi_setup_msi_irqs() on a RISCV platform which does not provide PCI/MSI support:

WARNING: CPU: 1 PID: 1 at drivers/pci/msi/msi.h:121 pci_msi_setup_msi_irqs+0x2c/0x32 __pci_enable_msix_range+0x30c/0x596 pci_msi_setup_msi_irqs+0x2c/0x32 pci_alloc_irq_vectors_affinity+0xb8/0xe2

RISCV uses hierarchical interrupt domains and correctly does not implement the legacy fallback. The warning triggers from the legacy fallback stub.

That warning is bogus as the PCI/MSI layer knows whether a PCI/MSI parent domain is associated with the device or not. There is a check for MSI-X, which has a legacy assumption. But that legacy fallback assumption is only valid when legacy support is enabled, but otherwise the check should simply return -ENOTSUPP.

Loongarch tripped over the same problem and blindly enabled legacy support without implementing the legacy fallbacks. There are weak implementations which return an error, so the problem was papered over.

Correct pci_msi_domain_supports() to evaluate the legacy mode and add the missing supported check into the MSI enable path to complete it.(CVE-2024-56760)

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

NFS: fix nfs_release_folio() to not deadlock via kcompactd writeback

Add PF_KCOMPACTD flag and current_is_kcompactd() helper to check for it so nfs_release_folio() can skip calling nfs_wb_folio() from kcompactd.

Otherwise NFS can deadlock waiting for kcompactd enduced writeback which recurses back to NFS (which triggers writeback to NFSD via NFS loopback mount on the same host, NFSD blocks waiting for XFS's call to __filemap_get_folio):

6070.550357] INFO: task kcompactd0:58 blocked for more than 4435 seconds.

{--- [58] "kcompactd0" [<0>]…

Record: OESA-2026-2417
CVSS 3.1: 9.1 CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
Updated: 2026-11-02

OSV Score usedOESA-2026-2418 9.1