Description
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.
Published: 2024-01-05
Score: 4.7 Medium
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

No analysis available yet.

Remediation

Vendor Workaround

Running only HVM or PVH VMs will avoid the vulnerability.

Tracking

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Advisories
Source ID Title
EUVD EUVD EUVD-2023-51002 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.
History

Tue, 04 Nov 2025 20:30:00 +0000

Type Values Removed Values Added
References

Tue, 03 Jun 2025 15:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


cve-icon MITRE

Status: PUBLISHED

Assigner: XEN

Published:

Updated: 2025-11-04T19:25:42.692Z

Reserved: 2023-10-27T07:55:35.332Z

Link: CVE-2023-46836

cve-icon Vulnrichment

Updated: 2025-11-04T19:25:42.692Z

cve-icon NVD

Status : Modified

Published: 2024-01-05T17:15:11.197

Modified: 2025-11-04T20:17:10.557

Link: CVE-2023-46836

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses