# CVE-2023-46836: x86: BTC/SRSO fixes not fully effective

> A race condition in Xen hypervisor allows malicious guests to bypass speculative execution mitigations, enabling Branch Type Confusion and Return Stack Overflow attacks.

- **Severity:** Medium 4.7 (`CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 5 Jan 2024
- **Updated:** 4 Nov 2025
- **Also known as:** ALPINE-CVE-2023-46836, DEBIAN-CVE-2023-46836, GHSA-4rmw-8gh7-w6g3, UBUNTU-CVE-2023-46836

## What is CVE-2023-46836?

CVE-2023-46836 is a medium-severity vulnerability in Xen Xen, published on 5 Jan 2024. It can only be exploited from the same machine or local network, with no action from the victim.

### Official 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.

## Which versions are affected by CVE-2023-46836?

It affects 1 product.


Products: Xen Xen.

## How do I fix CVE-2023-46836?

Apply the vendor's patch.

## Is CVE-2023-46836 being exploited?

There is no known exploitation of CVE-2023-46836 in the wild and no public exploit code.

## Other vulnerabilities in Xen Xen

- [CVE-2017-10912](https://insights.sbomify.com/CVE-2017-10912/): Privilege escalation in n/a (critical 10.0)
- [CVE-2017-10918](https://insights.sbomify.com/CVE-2017-10918/): Memory corruption in n/a (critical 10.0)
- [CVE-2017-10920](https://insights.sbomify.com/CVE-2017-10920/): Memory corruption in n/a (critical 10.0)
- [CVE-2017-10921](https://insights.sbomify.com/CVE-2017-10921/): Memory corruption in n/a (critical 10.0)
- [CVE-2025-27466](https://insights.sbomify.com/CVE-2025-27466/): Mutiple vulnerabilities in the Viridian interface (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-46836 and fix it if it is affected.

What it is: CVE-2023-46836 is a medium-severity vulnerability in Xen Xen, published on 5 Jan 2024. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2023-46836 in the wild and no public exploit code.

Affected product: Xen Xen. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2023-46836/ (Markdown: https://insights.sbomify.com/CVE-2023-46836/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-46836
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-46836
- OSV: https://osv.dev/vulnerability/CVE-2023-46836

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-46836/
Summaries are generated and may contain mistakes; the official description above is the record.