CVE-2023-46836

2024-01-0517:15:11

[email protected]

web.nvd.nist.gov

cve-2023-46836

xsa-422

xsa-434

irq-safe

speculative return stack overflow

meltdown

xpti

race condition

cpu vendors

nvd

4.7 Medium

CVSS3

Attack Vector

LOCAL

Attack Complexity

HIGH

Privileges Required

LOW

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

HIGH

Integrity Impact

NONE

Availability Impact

NONE

CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N

5.1 Medium

AI Score

Confidence

High

0.0004 Low

EPSS

Percentile

9.1%

JSON

The fixes for XSA-422 (Branch Type Confusion) and XSA-434 (Speculative
Return Stack Overflow) are not IRQ-safe. It was believed that the
mitigations always operated in contexts with IRQs disabled.

However, the original XSA-254 fix for Meltdown (XPTI) deliberately left
interrupts enabled on two entry paths; one unconditionally, and one
conditionally on whether XPTI was active.

As BTC/SRSO and Meltdown affect different CPU vendors, the mitigations
are not active together by default. Therefore, there is a race
condition whereby a malicious PV guest can bypass BTC/SRSO protections
and launch a BTC/SRSO attack against Xen.

Affected configurations

NVD

Node

xenxen

CPENameOperatorVersion
xen:xenxeneq*

CPE	Name	Operator	Version
xen:xen	xen	eq	*

CNA Affected

[
  {
    "defaultStatus": "unknown",
    "product": "Xen",
    "vendor": "Xen",
    "versions": [
      {
        "status": "unknown",
        "version": "consult Xen advisory XSA-446"
      }
    ]
  }
]