Kernel memory corruption via raced checksum metadata
Published Jun 25, 2026 · Updated Jun 25, 2026
TOCTOU race in Linux Kernel 6.8 and later allows local users to trigger out-of-bounds access through AF_XDP TX metadata. In xsk_skb_metadata(), the kernel validates csum_start and csum_offset from writable UMEM, then rereads them for skb assignment instead of reusing the checked values. A local low-privilege application must win the race between those reads; changed offsets bypass bounds checks and corrupt memory during transmit checksum computation.
Summary
What happened
TOCTOU race in Linux Kernel 6.8 and later allows local users to trigger out-of-bounds access through AF_XDP TX metadata. In xsk_skb_metadata(), the kernel validates csum_start and csum_offset from writable UMEM, then rereads them for skb assignment instead of reusing the checked values. A local low-privilege application must win the race between those reads; changed offsets bypass bounds checks and corrupt memory during transmit checksum computation.
The record
- CVE
- CVE-2026-53250
- Published
- Jun 25, 2026
- Updated
- Jun 25, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux Kernel
- Classifications
- CWE-367
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Jun 25, 2026CVE publishedPublication date reported by the CVE source.
- Jun 25, 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=48eb03dd26304c24f03bdbb9382e89c8564e71df <0dfe05b938435892875e07771170051346412df9
- Affected versionversion=48eb03dd26304c24f03bdbb9382e89c8564e71df <22ba97ea9cc1f63a0d0244fae38057ed452b6ac7
- Affected versionversion=48eb03dd26304c24f03bdbb9382e89c8564e71df <bfdfd2706d5fb2cd496a1506e680daf979309c8b
- Affected versionversion=6.8
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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