CVE-2026-31600 — arm64: mm: Handle invalid large leaf mappings correctly

Affected: Linux

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

arm64: mm: Handle invalid large leaf mappings correctly

It has been possible for a long time to mark ptes in the linear map as invalid. This is done for secretmem, kfence, realm dma memory un/share, and others, by simply clearing the PTE_VALID bit. But until commit a166563e7ec37 ("arm64: mm: support large block mapping when rodata=full") large leaf mappings were never made invalid in this way.

It turns out various parts of the code base are not equipped to handle invalid large leaf mappings (in the way they are currently encoded) and I've observed a kernel panic while booting a realm guest on a BBML2_NOABORT system as a result:

[ 15.432706] software IO TLB: Memory encryption is active and system is using DMA bounce buffers [ 15.476896] Unable to handle kernel paging request at virtual address ffff000019600000 [ 15.513762] Mem abort info: [ 15.527245] ESR = 0x0000000096000046 [ 15.548553] EC = 0x25: DABT (current EL), IL = 32 bits [ 15.572146] SET = 0, FnV = 0 [ 15.592141] EA = 0, S1PTW = 0 [ 15.612694] FSC = 0x06: level 2 translation fault [ 15.640644] Data abort info: [ 15.661983] ISV = 0, ISS = 0x00000046, ISS2 = 0x00000000 [ 15.694875] CM = 0, WnR = 1, TnD = 0, TagAccess = 0 [ 15.723740] GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0 [ 15.755776] swapper pgtable: 4k pages, 48-bit VAs, pgdp=0000000081f3f000 [ 15.800410] [ffff000019600000] pgd=0000000000000000, p4…

USN-8488-1 — linux, linux-aws, linux-gcp, linux-ibm, linux-oracle, linux-realtime vulnerabilities

Affected: Ubuntu:26.04:LTS: linux, Ubuntu:26.04:LTS: linux-aws, Ubuntu:26.04:LTS: linux-gcp, Ubuntu:26.04:LTS: linux-ibm, Ubuntu:26.04:LTS: linux-oracle, Ubuntu:26.04:LTS: linux-realtime

It was discovered that some AMD processors did not properly clear data in the floating point divider unit during speculative execution. A local attacker could use this to expose sensitive information. (CVE-2025-54505)

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; - x86 architecture; - Block layer subsystem; - Cryptographic API; - Rados block device (RBD) driver; - Compressed RAM block device driver; - Character device driver; - TPM device driver; - Hardware crypto device drivers; - EDAC drivers; - GPU drivers; - Greybus drivers; - HID subsystem; - Microsoft Hyper-V drivers; - Hardware monitoring drivers; - I2C subsystem; - IIO subsystem; - InfiniBand drivers; - Input Device core drivers; - LED subsystem; - Multiple devices driver; - Media drivers; - IBM Advanced System Management driver; - MTD block device drivers; - Network drivers; - Microsoft Azure Network Adapter (MANA) driver; - NTB driver; - NVME drivers; - Device tree and open firmware driver; - PCI subsystem; - Remote Processor subsystem; - SCSI subsystem; - SPI subsystem; - Realtek RTL8723BS SDIO drivers; - SM750 framebuffer staging driver; - Thermal drivers; - USB Gadget drivers; - USB over IP driver; - VFIO drivers; - Framebuffer layer; - 9P distributed file system; - AFS file…

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CVE-2026-31600 — arm64: mm: Handle invalid large leaf mappings correctly

USN-8488-1 — linux, linux-aws, linux-gcp, linux-ibm, linux-oracle, linux-realtime vulnerabilities