UBUNTU-CVE-2023-46836

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    UBUNTU-CVE-2023-46836

    Published: 5 Jan 2024Last Modified: 17 Oct 2026
    Upstream:
    CVE-2023-46836

    Summary:

    Details: 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.

    References: https://ubuntu.com/security/CVE-2023-46836, https://xenbits.xen.org/xsa/advisory-446.html, https://www.cve.org/CVERecord?id=CVE-2023-46836

    Affected packages

    Package

    Name: xen

    Purl: pkg:deb/ubuntu/xen?arch=source&distro=xenial

    Affected ranges

    Type: ECOSYSTEM

    Events:

    Introduced- 0
    Fixed -None

    Affected versions

    4.5.1-0ubuntu1
    4.5.1-0ubuntu2

    Common Vulnerability Scoring System

    Attack Vector
    Network
    Adjacent
    Local
    Physical
    Privileges Required
    None
    Low
    High
    User Interaction
    None
    Required
    Scope
    Unchanged
    Changed
    Confidentiality
    None
    Low
    High
    Integrity
    None
    Low
    High
    Availability
    None
    Low
    High
    UBUNTU-CVE-2023-46836 | CVE-DB