Kernel-stack disclosure via uninitialized header padding
Published May 28, 2026 · Updated May 28, 2026
Information disclosure in Linux Kernel allows local users to read kernel stack data through the pseries papr-hvpipe interface. The papr-hvpipe header-return path initializes only hdr.version and hdr.flags before copy_to_user() returns reserved bytes that still contain stack data. Reachability requires low-privileged local access to a Power pSeries system exposing this interface, and the consequence is disclosure of residual stack bytes.
Summary
What happened
Information disclosure in Linux Kernel allows local users to read kernel stack data through the pseries papr-hvpipe interface. The papr-hvpipe header-return path initializes only hdr.version and hdr.flags before copy_to_user() returns reserved bytes that still contain stack data. Reachability requires low-privileged local access to a Power pSeries system exposing this interface, and the consequence is disclosure of residual stack bytes.
The record
- CVE
- CVE-2026-46182
- Published
- May 28, 2026
- Updated
- May 28, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux Kernel
- Classifications
- CWE-401
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- May 28, 2026CVE publishedPublication date reported by the CVE source.
- May 28, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=6.18
- Affected versionversion=cebdb522fd3edd1fe05f7b4a74a27da7dd0f8d86 <0479b6e9f999cc1cbad7d9f09f574fc387e605d5
- Affected versionversion=cebdb522fd3edd1fe05f7b4a74a27da7dd0f8d86 <cefeed44296261173a806bef988b26bc565da4be
- Affected versionversion=cebdb522fd3edd1fe05f7b4a74a27da7dd0f8d86 <f88f8e4485b437e0a2f96a7ff1f88aa22d925659
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
Check the software in your environment
Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.
Book a demo