CVE-2023-46836 — The fixes for XSA-422 (Branch Type Confusion) and XSA-434 (Speculative Return St

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.

01What is this vulnerability?

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.

02Affected products

Vendor	Product	Versions
Xen	Xen	consult Xen advisory XSA-446

03Active exploitation status

Not currently listed on the CISA Known Exploited Vulnerabilities (KEV) catalog. EPSS is the best forward-looking signal — see the EPSS row above.

04Recommended remediation

• Patch to a fixed version listed in the vendor advisory (see references below).
• Mitigate with WAF rules, network egress filters, or feature flags where the patch is not yet available.
• Hunt historical logs for exploitation indicators — see Detection signatures below.

05Technical details

For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.

06Detection signatures

Ask SARA in chat to draft a starting detection for this CVE in your stack of choice.

07Related CVEs

No directly-cited follow-up CVEs in the KB record for this advisory. The references list in section 09 carries the vendor cross-references.

08Timeline

• Published: 2024-01-05T16:34:59.036Z
• Last modified: 2025-11-04T19:25:42.692Z

09References

• xenbits.xenproject.org — https://xenbits.xenproject.org/xsa/advisory-446.html