DEBIAN-CVE-2026-23107

In the Linux kernel, the following vulnerability has been resolved: arm64/fpsimd: signal: Allocate SSVE storage when restoring ZA The code to restore a ZA context doesn't attempt to allocate the task's sve_state before setting TIF_SME. Consequently, restoring a ZA context can place a task into an invalid state where TIF_SME is set but the task's sve_state is NULL. In legitimate but uncommon cases where the ZA signal context was NOT created by the kernel in the context of the same task (e.g. if the task is saved/restored with something like CRIU), we have no guarantee that sve_state had been allocated previously. In these cases, userspace can enter streaming mode without trapping while sve_state is NULL, causing a later NULL pointer dereference when the kernel attempts to store the register state: | # ./sigreturn-za | Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000 | Mem abort info: | ESR = 0x0000000096000046 | EC = 0x25: DABT (current EL), IL = 32 bits | SET = 0, FnV = 0 | EA = 0, S1PTW = 0 | FSC = 0x06: level 2 translation fault | Data abort info: | ISV = 0, ISS = 0x00000046, ISS2 = 0x00000000 | CM = 0, WnR = 1, TnD = 0, TagAccess = 0 | GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0 | user pgtable: 4k pages, 52-bit VAs, pgdp=0000000101f47c00 | [0000000000000000] pgd=08000001021d8403, p4d=0800000102274403, pud=0800000102275403, pmd=0000000000000000 | Internal error: Oops: 0000000096000046 [#1] SMP | Modules linked in: | CPU: 0 UID: 0 PID: 153 Comm: sigreturn-za Not tainted 6.19.0-rc1 #1 PREEMPT | Hardware name: linux,dummy-virt (DT) | pstate: 214000c9 (nzCv daIF +PAN -UAO -TCO +DIT -SSBS BTYPE=--) | pc : sve_save_state+0x4/0xf0 | lr : fpsimd_save_user_state+0xb0/0x1c0 | sp : ffff80008070bcc0 | x29: ffff80008070bcc0 x28: fff00000c1ca4c40 x27: 63cfa172fb5cf658 | x26: fff00000c1ca5228 x25: 0000000000000000 x24: 0000000000000000 | x23: 0000000000000000 x22: fff00000c1ca4c40 x21: fff00000c1ca4c40 | x20:...