CVE-2026-89481

Summary

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 Software

VendorProductVersion RangeStatus
LinuxLinux3f2304f8c6d6ed97849057bd16fee99e434ca796 < a4c3c7310156493797c920b10d8648c07aa05403affected
LinuxLinux3f2304f8c6d6ed97849057bd16fee99e434ca796 < 3b3d27670c0c890ba7cf1bc3614cab61bde6d25caffected
LinuxLinux3f2304f8c6d6ed97849057bd16fee99e434ca796 < 3a0b05145053a5fad1a2ddb4e4d87b07385e63e5affected
LinuxLinux3f2304f8c6d6ed97849057bd16fee99e434ca796 < 6efbc52237facda35d2d874fe1765bb4839275d8affected
LinuxLinux5.0affected
LinuxLinux0 < 5.0unaffected
LinuxLinux6.12.109 <= 6.12.*unaffected
LinuxLinux6.18.50 <= 6.18.*unaffected
LinuxLinux7.2.4 <= 7.2.*unaffected
LinuxLinux7.3-rc1 <= *unaffected

Weaknesses

References