Vulnerability record · CVE-2026-89743 · published 11 September 2026
CVE-2026-89743: In the Linux kernel, the following vulnerability has been resolved: misc: nsm: bound the device-reported resp…
In the Linux kernel, the following vulnerability has been resolved: misc: nsm: bound the device-reported response length nsm_sendrecv_msg_locked() stores the virtqueue used-ring length reported by the NSM device into msg->resp.len without bounding it to the response buffer. A malicious or buggy backend can report a length larger than the response buffer; parse_resp_raw() then copies that many bytes out of the fixed buffer to user space, disclosing adjacent kernel heap (an out-of-bounds read). The request path already floors its length in fill_req_raw(); the response path lacks the symmetric check. Clamp the stored length to the size of the response buffer. Well-behaved devices report no more than the posted buffer size, so conforming traffic is unaffected.
Description
In the Linux kernel, the following vulnerability has been resolved: misc: nsm: bound the device-reported response length nsm_sendrecv_msg_locked() stores the virtqueue used-ring length reported by the NSM device into msg->resp.len without bounding it to the response buffer. A malicious or buggy backend can report a length larger than the response buffer; parse_resp_raw() then copies that many bytes out of the fixed buffer to user space, disclosing adjacent kernel heap (an out-of-bounds read). The request path already floors its length in fill_req_raw(); the response path lacks the symmetric check. Clamp the stored length to the size of the response buffer. Well-behaved devices report no more than the posted buffer size, so conforming traffic is unaffected.
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
References
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Source: NIST National Vulnerability Database (record CVE-2026-89743), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.
