# CVE-2026-89481

## Summary

- **CVE ID:** CVE-2026-89481
- **Severity:** HIGH
- **CVSS Score:** 7.5 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N)
- **CWE:** N/A
- **Published:** Sep 11, 2026
- **Last Modified:** Sep 14, 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.

## Affected Products

- Linux — Linux (3f2304f8c6d6ed97849057bd16fee99e434ca796)
- Linux — Linux (5.0)
- Linux — Linux (0)
- Linux — Linux (6.12.109)
- Linux — Linux (6.18.50)
- Linux — Linux (7.2.4)
- Linux — Linux (7.3-rc1)
- Linux — Linux (6.1.188)
- Linux — Linux (6.6.157)

## References

- [CNA](https://git.kernel.org/stable/c/a4c3c7310156493797c920b10d8648c07aa05403)
- [CNA](https://git.kernel.org/stable/c/3b3d27670c0c890ba7cf1bc3614cab61bde6d25c)
- [CNA](https://git.kernel.org/stable/c/3a0b05145053a5fad1a2ddb4e4d87b07385e63e5)
- [CNA](https://git.kernel.org/stable/c/6efbc52237facda35d2d874fe1765bb4839275d8)
- [CNA](https://git.kernel.org/stable/c/49a4dcf57608ebf6432dbcb203ed25e7ed581445)
- [CNA](https://git.kernel.org/stable/c/bc4013c7cce58d46f792c8c87bc8c8318a70190e)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.41%
- **EPSS Percentile:** 35.0

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-18._