Linux Distros Unpatched Vulnerability : CVE-2025-38670

critical Nessus Plugin ID 260270

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Synopsis

The Linux/Unix host has one or more packages installed with a vulnerability that the vendor indicates will not be patched.

Description

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

- arm64/entry: Mask DAIF in cpu_switch_to(), call_on_irq_stack() `cpu_switch_to()` and `call_on_irq_stack()` manipulate SP to change to different stacks along with the Shadow Call Stack if it is enabled. Those two stack changes cannot be done atomically and both functions can be interrupted by SErrors or Debug Exceptions which, though unlikely, is very much broken : if interrupted, we can end up with mismatched stacks and Shadow Call Stack leading to clobbered stacks. In `cpu_switch_to()`, it can happen when SP_EL0 points to the new task, but x18 stills points to the old task's SCS. When the interrupt handler tries to save the task's SCS pointer, it will save the old task SCS pointer (x18) into the new task struct (pointed to by SP_EL0), clobbering it. In `call_on_irq_stack()`, it can happen when switching from the task stack to the IRQ stack and when switching back. In both cases, we can be interrupted when the SCS pointer points to the IRQ SCS, but SP points to the task stack. The nested interrupt handler pushes its return addresses on the IRQ SCS. It then detects that SP points to the task stack, calls `call_on_irq_stack()` and clobbers the task SCS pointer with the IRQ SCS pointer, which it will also use ! This leads to tasks returning to addresses on the wrong SCS, or even on the IRQ SCS, triggering kernel panics via CONFIG_VMAP_STACK or FPAC if enabled. This is possible on a default config, but unlikely. However, when enabling CONFIG_ARM64_PSEUDO_NMI, DAIF is unmasked and instead the GIC is responsible for filtering what interrupts the CPU should receive based on priority. Given the goal of emulating NMIs, pseudo-NMIs can be received by the CPU even in `cpu_switch_to()` and `call_on_irq_stack()`, possibly *very* frequently depending on the system configuration and workload, leading to unpredictable kernel panics. Completely mask DAIF in `cpu_switch_to()` and restore it when returning. Do the same in `call_on_irq_stack()`, but restore and mask around the branch. Mask DAIF even if CONFIG_SHADOW_CALL_STACK is not enabled for consistency of behaviour between all configurations. Introduce and use an assembly macro for saving and masking DAIF, as the existing one saves but only masks IF. (CVE-2025-38670)

Note that Nessus relies on the presence of the package as reported by the vendor.

Solution

There is no known solution at this time.

Plugin Details

Severity: Critical

ID: 260270

File Name: unpatched_CVE_2025_38670.nasl

Version: 1.1

Type: local

Agent: unix

Family: Misc.

Published: 9/2/2025

Updated: 9/2/2025

Supported Sensors: Frictionless Assessment Agent, Nessus Agent, Agentless Assessment, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 6.7

CVSS v2

Risk Factor: High

Base Score: 7.5

Temporal Score: 5.5

Vector: CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:P

CVSS Score Source: CVE-2025-38670

CVSS v3

Risk Factor: Critical

Base Score: 9.8

Temporal Score: 8.5

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

Vulnerability Information

CPE: p-cpe:/a:debian:debian_linux:linux, cpe:/o:debian:debian_linux:14.0, cpe:/o:debian:debian_linux:12.0

Required KB Items: Host/local_checks_enabled, Host/cpu, global_settings/vendor_unpatched, Host/OS/identifier

Exploit Ease: No known exploits are available

Vulnerability Publication Date: 8/22/2025

Reference Information

CVE: CVE-2025-38670

Detections

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