Linux Kernel XDP XSK Metadata Pointer Race Leak Timestamp
CVE-2026-74709 Published on August 22, 2026
xsk: clear metadata pointer when no timestamp is requested
In the Linux kernel, the following vulnerability has been resolved:
xsk: clear metadata pointer when no timestamp is requested
User space can change metadata flags after request processing. Rereading
them during completion can therefore make the kernel write a timestamp
that was not requested when the packet was submitted.
Clear the metadata pointer during request processing unless timestamp
completion is requested. Completion handling can then use the pointer
itself instead of rereading the flags.
On the mlx5 multi-packet WQE path metadata is evaluated per batch:
xsk_tx_metadata_request() runs only for the descriptor that starts a
session, just like the checksum offload that is applied once through the
shared WQE. Only that descriptor's pointer is reset, so completion
handling can record a timestamp for the other descriptors of the session
regardless of their own XDP_TXMD_FLAGS_TIMESTAMP bit. The write stays
inside the metadata area; the single-WQE, other zero-copy, and generic
paths reset the pointer per descriptor and are unaffected.
Products Associated with CVE-2026-74709
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Affected Versions
Linux:- Version ca4419f15abd19ba8be1e109661b60f9f5b6c9f0 and below 0ba2e1eb07a826d021344e2f146b6716c58139eb is affected.
- Version ca4419f15abd19ba8be1e109661b60f9f5b6c9f0 and below eb4c613d4ebc3f664e70d572b8867ba114a8754e is affected.
- Version ca4419f15abd19ba8be1e109661b60f9f5b6c9f0 and below 9f60a67df8d3c862503bee62bada8e7089cba438 is affected.
- Version d9d736c416c9a85f84e15435ba82a177262e745b is affected.
- Version 6.14.2 and below 6.15 is affected.
- Version 6.15 is affected.
- Before 6.15 is unaffected.
- Version 6.18.45, <= 6.18.* is unaffected.
- Version 7.1.9, <= 7.1.* is unaffected.
- Version 7.2, <= * is unaffected.