Local kernel crash via collect_md interface double-free
Published Aug 12, 2025 · Updated Aug 5, 2026
Use-after-free in Linux kernel 6.1 allows local users to crash the kernel through collect_md xfrm interface changes. xfrmi_changelink() misses the creation-only collect_md check, inserts the same interface into the xfrmi hash while retaining collect_md_xfrmi, and causes two frees during network-namespace teardown. The path requires CAP_NET_ADMIN in a network namespace; unprivileged user namespaces can supply it, and reuse of the freed net_device enables kernel memory disclosure, writes, or control-flow hijacking.
Summary
What happened
Use-after-free in Linux kernel 6.1 allows local users to crash the kernel through collect_md xfrm interface changes. xfrmi_changelink() misses the creation-only collect_md check, inserts the same interface into the xfrmi hash while retaining collect_md_xfrmi, and causes two frees during network-namespace teardown. The path requires CAP_NET_ADMIN in a network namespace; unprivileged user namespaces can supply it, and reuse of the freed net_device enables kernel memory disclosure, writes, or control-flow hijacking.
The record
- CVE
- CVE-2025-38500
- Published
- Aug 12, 2025
- Updated
- Aug 5, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- CWE-416, T1499.004
- Attack vector
- local
- Privileges
- Unavailable
Timeline
How it unfolded
- Aug 12, 2025CVE publishedPublication date reported by the CVE source.
- Aug 5, 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?
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- Affected versionversion=6.1
- Affected versionversion=abc340b38ba25cd6c7aa2c0bd9150d30738c82d0 <5918c3f4800a3aef2173865e5903370f21e24f47
- Affected versionversion=abc340b38ba25cd6c7aa2c0bd9150d30738c82d0 <69a31f7a6a81f5ffd3812c442e09ff0be22960f1
- Affected versionversion=abc340b38ba25cd6c7aa2c0bd9150d30738c82d0 <a8d4748b954584ab7bd800f1a4e46d5b0eeb5ce4
- Affected versionversion=abc340b38ba25cd6c7aa2c0bd9150d30738c82d0 <a90b2a1aaacbcf0f91d7e4868ad6c51c5dee814b
- Affected versionversion=abc340b38ba25cd6c7aa2c0bd9150d30738c82d0 <bfebdb85496e1da21d3cf05de099210915c3e706
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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