CVE-2026-89481nvme-tcp: fix host memory disclosure on R2T for a read command

Official description

In the Linux kernel, the following vulnerability has been resolved: nvme-tcp: fix host memory disclosure on R2T for a read command nvme_tcp_handle_r2t() does not check the direction of the request the R2T refers to. A malicious controller can send an R2T for a READ and the host will answer it: nvme_tcp_setup_h2c_data_pdu() builds the H2CData header and nvme_tcp_try_send_data() sends the request's data buffer. That buffer is the READ destination, so its contents go to the controller. The command then completes normally and nothing is logged. Against a test controller that answers every READ with an R2T, a 4096 byte buffered read returned all 4096 bytes, split over two R2Ts. The pages contained stale kernel data, including an array of struct page pointers. Reject an R2T for a request that is not a write.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/effe898669c5f69ed519d6339be01ee9cd91d1a4
• https://git.kernel.org/stable/c/377aa04d7b3e73ffef6364818def188da8d6f025
• https://git.kernel.org/stable/c/49a4dcf57608ebf6432dbcb203ed25e7ed581445
• https://git.kernel.org/stable/c/bc4013c7cce58d46f792c8c87bc8c8318a70190e
• https://git.kernel.org/stable/c/a4c3c7310156493797c920b10d8648c07aa05403
• https://git.kernel.org/stable/c/3b3d27670c0c890ba7cf1bc3614cab61bde6d25c
• https://git.kernel.org/stable/c/3a0b05145053a5fad1a2ddb4e4d87b07385e63e5
• https://git.kernel.org/stable/c/6efbc52237facda35d2d874fe1765bb4839275d8