| CVE-2023-46836 | Date: (C)2023-12-21 (M)2024-04-26 |
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.
CVSS Score and Metrics +CVSS Score and Metrics -| CVSS V3 Severity: | CVSS V2 Severity: |
| CVSS Score : 4.7 | CVSS Score : |
| Exploit Score: 1.0 | Exploit Score: |
| Impact Score: 3.6 | Impact Score: |
| |
| CVSS V3 Metrics: | CVSS V2 Metrics: |
| Attack Vector: LOCAL | Access Vector: |
| Attack Complexity: HIGH | Access Complexity: |
| Privileges Required: LOW | Authentication: |
| User Interaction: NONE | Confidentiality: |
| Scope: UNCHANGED | Integrity: |
| Confidentiality: HIGH | Availability: |
| Integrity: NONE | |
| Availability: NONE | |
| | |
