---
id: "CVE-2026-98648"
kind: "vulnerability"
aliases: ["CVE-2026-98648"]
title: "Linux s390 kernel: out-of-bounds read when many UV secrets stored"
severity: "low"
cvss: null
epss: null
exploited: false
status: "open"
category: "runtime"
products: []
ecosystems: []
tags: ["ibm-z", "linux-kernel", "runtime", "s390"]
not_affected_if: ["non-s390-architecture"]
published_at: "2026-10-18T16:17:18+00:00"
first_seen_at: "2026-10-23T21:57:16+00:00"
updated_at: "2026-10-25T05:20:49+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-98648", "first_seen_at": "2026-10-23T21:57:16+00:00"}]
---

# Linux s390 kernel: out-of-bounds read when many UV secrets stored

On IBM s390 Linux systems with more than 85 Ultravisor secrets, the lookup code in find_secret_in_page reads past the end of a page when the target secret is on the next page or absent. The fix bounds the loop to the number of secrets stored in each sub-list.

_Summary, check and fix written by a model from the sources; labelled as such._

## Timeline

- 2026-10-23T21:57:16+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-98648

## From the sources

In the Linux kernel, the following vulnerability has been resolved:

s390/uv: Prevent potential out-of-bounds read

When the system has more than 85 secrets, the uv_secret_list struct
array only holds up to 85 items per page, resulting in an out of bounds
read in find_secret_in_page if the targeted secret is in the next page
or not stored at all.

Fix this by looping over the number of stored secrets which is the
per sub-list count of stored secrets and not the overall count.

---

_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_