Vulnerability 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.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Xen | Xen | All versions |
References
- https://xenbits.xenproject.org/xsa/advisory-446.htmlPatchVendor Advisory
- http://xenbits.xen.org/xsa/advisory-446.html
- https://xenbits.xenproject.org/xsa/advisory-446.htmlPatchVendor Advisory
FAQ
What is CVE-2023-46836?
CVE-2023-46836 is a vulnerability with a CVSS score of 4.7 (MEDIUM). 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. H...
How severe is CVE-2023-46836?
CVE-2023-46836 has been rated MEDIUM with a CVSS base score of 4.7/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2023-46836?
Check the references section above for vendor advisories and patch information. Affected products include: Xen Xen.