x86: BTC/SRSO fixes not fully effective (Xen Xen)
At a glance
- Source
- NVD
- EPSS
- EPSS 0.25 % · percentile 16 ()
- State
- PUBLISHED
- Published
- Updated
- Assigner
- XEN
- NVD status
- Modified
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.
References
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 3.1 | MEDIUM 4.7 | CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N | CISA-ADP |
| CVSS 3.1 | MEDIUM 4.7 | CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N | NVD · nvd@nist.gov (Primary) |
| CVSS 3.1 | MEDIUM 4.7 | CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N | NVD · 134c704f-9b21-4f2e-91b3-4a467353bcc0 (Secondary) |
European references
- ENISA EUVD · EUVD-2023-51002
- GCVE · GCVE-0-2023-46836
CERT-FR advisories
- CERTFR-2023-AVI-0938 — Multiples vulnérabilités dans Xen · cert.ssi.gouv.fr
Affected configurations (NVD CPE)
cpe:2.3:o:xen:xen:*:*:*:*:*:*:*:*
Affected products
| Product | Versions |
|---|---|
| Xen · Xen | unknown consult Xen advisory XSA-446 |
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| CERT-FR (ANSSI) | Licence Ouverte / Etalab 2.0 |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |