CVE-2026-23107
Vulnerability Scoring
Status: Awaiting Analysis
Last updated: 🕔 06 Feb 2026, 17:16 UTC
Originally published on: 🕔 04 Feb 2026, 17:16 UTC
Time between publication and last update: 2 days
CVSS Release:
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: 0000000000000020 x19: fff00000ff6900f0 x18: 0000000000000000 | x17: fff05e8e0311f000 x16: 0000000000000000 x15: 028fca8f3bdaf21c | x14: 0000000000000212 x13: fff00000c0209f10 x12: 0000000000000020 | x11: 0000000000200b20 x10: 0000000000000000 x9 : fff00000ff69dcc0 | x8 : 00000000000003f2 x7 : 0000000000000001 x6 : fff00000c1ca5b48 | x5 : fff05e8e0311f000 x4 : 0000000008000000 x3 : 0000000000000000 | x2 : 0000000000000001 x1 : fff00000c1ca5970 x0 : 0000000000000440 | Call trace: | sve_save_state+0x4/0xf0 (P) | fpsimd_thread_switch+0x48/0x198 | __switch_to+0x20/0x1c0 | __schedule+0x36c/0xce0 | schedule+0x34/0x11c | exit_to_user_mode_loop+0x124/0x188 | el0_interrupt+0xc8/0xd8 | __el0_irq_handler_common+0x18/0x24 | el0t_64_irq_handler+0x10/0x1c | el0t_64_irq+0x198/0x19c | Code: 54000040 d51b4408 d65f03c0 d503245f (e5bb5800) | ---[ end trace 0000000000000000 ]--- Fix this by having restore_za_context() ensure that the task's sve_state is allocated, matching what we do when taking an SME trap. Any live SVE/SSVE state (which is restored earlier from a separate signal context) must be preserved, and hence this is not zeroed.
The exploitability of CVE-2026-23107 depends on two key factors: attack complexity (the level of effort required to execute an exploit) and privileges required (the access level an attacker needs).
No exploitability data is available for CVE-2026-23107.
A lower complexity and fewer privilege requirements make exploitation easier. Security teams should evaluate these aspects to determine the urgency of mitigation strategies, such as patch management and access control policies.
Attack Complexity (AC) measures the difficulty in executing an exploit. A high AC means that specific conditions must be met, making an attack more challenging, while a low AC means the vulnerability can be exploited with minimal effort.
Privileges Required (PR) determine the level of system access necessary for an attack. Vulnerabilities requiring no privileges are more accessible to attackers, whereas high privilege requirements limit exploitation to authorized users with elevated access.
Above is the CVSS Sub-score Breakdown for CVE-2026-23107, illustrating how Base, Impact, and Exploitability factors combine to form the overall severity rating. A higher sub-score typically indicates a more severe or easier-to-exploit vulnerability.
Below is the Impact Analysis for CVE-2026-23107, showing how Confidentiality, Integrity, and Availability might be affected if the vulnerability is exploited. Higher values usually signal greater potential damage.
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