Cross-service namespace disclosure via permissive handle opening
Published May 8, 2026 · Updated May 8, 2026
Improper authorization in Linux Kernel 6.18 through 6.19.8 and 7.0-rc1 through 7.0-rc2 allows local users to access other services' namespaces. In fs/nsfs.c, nsfs_fh_to_dentry accepted a namespace file handle when ns_capable granted CAP_SYS_ADMIN in the handle's owning user namespace rather than applying may_see_all_namespaces. The path also requires CAP_DAC_READ_SEARCH for open_by_handle_at; the published description limits the consequence to cross-service information leakage.
Summary
What happened
Improper authorization in Linux Kernel 6.18 through 6.19.8 and 7.0-rc1 through 7.0-rc2 allows local users to access other services' namespaces. In fs/nsfs.c, nsfs_fh_to_dentry accepted a namespace file handle when ns_capable granted CAP_SYS_ADMIN in the handle's owning user namespace rather than applying may_see_all_namespaces. The path also requires CAP_DAC_READ_SEARCH for open_by_handle_at; the published description limits the consequence to cross-service information leakage.
The record
- CVE
- CVE-2026-43391
- Published
- May 8, 2026
- Updated
- May 8, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux Kernel
- Classifications
- Unavailable
- Attack vector
- local
- Privileges
- Unavailable
Timeline
How it unfolded
- May 8, 2026CVE publishedPublication date reported by the CVE source.
- May 8, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=5222470b2fbb3740f931f189db33dd1367b1ae75 <1797ee11451f1b2be69863a9f5bd43b948813fdf
- Affected versionversion=5222470b2fbb3740f931f189db33dd1367b1ae75 <d2324a9317f00013facb0ba00b00440e19d2af5e
- Affected versionversion=6.18
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
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Public exploit references
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Technologies
Your stack
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Your stack
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