Local memory corruption via zerocopy skb lifetime mismatch
Published Jul 19, 2026 · Updated Jul 19, 2026
Use-after-free in Linux Kernel's virtio-vsock transport allows local users to corrupt kernel memory via a crafted zerocopy send. virtio_transport_alloc_skb() fills the skb before binding its zerocopy uarg, so an -EMSGSIZE rollback releases managed fragment references under the wrong lifetime rule. A low-privilege local process needs a connected virtio-vsock socket, io_uring fixed-buffer zerocopy, and a vector exceeding MAX_SKB_FRAGS to reach the stale-memory path.
Summary
What happened
Use-after-free in Linux Kernel's virtio-vsock transport allows local users to corrupt kernel memory via a crafted zerocopy send. virtio_transport_alloc_skb() fills the skb before binding its zerocopy uarg, so an -EMSGSIZE rollback releases managed fragment references under the wrong lifetime rule. A low-privilege local process needs a connected virtio-vsock socket, io_uring fixed-buffer zerocopy, and a vector exceeding MAX_SKB_FRAGS to reach the stale-memory path.
The record
- CVE
- CVE-2026-63970
- Published
- Jul 19, 2026
- Updated
- Jul 19, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux Kernel
- Classifications
- Unavailable
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Jul 19, 2026CVE publishedPublication date reported by the CVE source.
- Jul 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=581512a6dc939ef122e49336626ae159f3b8a345 <1e584c304cfb94a759417130b1fc6d30b30c4cce
- Affected versionversion=581512a6dc939ef122e49336626ae159f3b8a345 <5d317573f1d48e76cce5fb6250452b6e4102e0fb
- Affected versionversion=581512a6dc939ef122e49336626ae159f3b8a345 <b62e2b2b4a50953ca952f3cd3f77dd62dc50fd5d
- Affected versionversion=6.7
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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