Local namespace isolation bypass via movable fallback device
Published Jun 19, 2026 · Updated Jun 19, 2026
Improper namespace isolation in Linux Kernel allows local users to move the ip6_vti0 fallback tunnel into another network namespace. vti6_init_net() leaves netns_immutable unset on the per-namespace fallback device, so the network core permits that device to migrate. Exploitation requires local low-privileged access; the CNA rates confidentiality, integrity, and availability impacts high but does not disclose the resulting attack primitive.
Summary
What happened
Improper namespace isolation in Linux Kernel allows local users to move the ip6_vti0 fallback tunnel into another network namespace. vti6_init_net() leaves netns_immutable unset on the per-namespace fallback device, so the network core permits that device to migrate. Exploitation requires local low-privileged access; the CNA rates confidentiality, integrity, and availability impacts high but does not disclose the resulting attack primitive.
The record
- CVE
- CVE-2026-52909
- Published
- Jun 19, 2026
- Updated
- Jun 19, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux Kernel
- Classifications
- Unavailable
- Attack vector
- local
- Privileges
- Unavailable
Timeline
How it unfolded
- Jun 19, 2026CVE publishedPublication date reported by the CVE source.
- Jun 19, 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=3.15
- Affected versionversion=61220ab349485d911083d0b7990ccd3db6c63297 <d289d5307762d1838aaece22c6b6fcad9e8865f9
- Affected versionversion=61220ab349485d911083d0b7990ccd3db6c63297 <dcdce3bc9f08026ff3739ee7339e1bef526fc5f3
- Affected versionversion=61220ab349485d911083d0b7990ccd3db6c63297 <ecf8904067dcba0dad86ece80874841e60317885
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
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Weakness, pattern, technique
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Public exploit references
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Technologies
Your stack
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Your stack
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