CVSS 3.1
4.7 mediumCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:NCVE-2023-46836
Medium (4.7) in xen xen. EPSS 0.2% chance of exploitation in the next 30 days.
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.
Severity
- EPSS
- 0.2% chance of exploitation in the next 30 days; higher than 16% of CVEs (scores of 2026-10-31)
- Published
- Modified
- Record from
- the NVD, synced
Affected
- xen:xen