CVE-2026-89481
Published: September 15, 2026Last modified: September 28, 2026
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.
Severity score breakdown
| Parameter | Value |
|---|---|
| Base score | 7.5 |
| Attack Vector | NETWORK |
| Attack complexity | LOW |
| Privileges required | NONE |
| User interaction | NONE |
| Scope | UNCHANGED |
| Confidentiality | HIGH |
| Integrity impact | NONE |
| Availability impact | NONE |
| Vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N |
Status
| Product | Release | Package | Status |
|---|---|---|---|
| Alpaquita Linux | 23 LTS | linux-lts | Vulnerable (6.1.182-r0) |
| 25 LTS | linux-lts | Fixed (6.12.111-r0) | |
| Stream | linux-lts | Fixed (6.18.53-r0) |
References
- https://git.kernel.org/stable/c/3a0b05145053a5fad1a2ddb4e4d87b07385e63e5
- https://git.kernel.org/stable/c/3b3d27670c0c890ba7cf1bc3614cab61bde6d25c
- https://git.kernel.org/stable/c/49a4dcf57608ebf6432dbcb203ed25e7ed581445
- https://git.kernel.org/stable/c/6efbc52237facda35d2d874fe1765bb4839275d8
- https://git.kernel.org/stable/c/a4c3c7310156493797c920b10d8648c07aa05403
- https://git.kernel.org/stable/c/bc4013c7cce58d46f792c8c87bc8c8318a70190e