misc: nsm: bound the device-reported response length (CVE-2026-89743) | HOL Guard CVE

Unknown severity · Source severity not reportedCVE-2026-89743

misc: nsm: bound the device-reported response length

Answer in brief

CVE-2026-89743 records a Unknown severity vulnerability in misc: nsm: bound the device-reported response length. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Sep 11, 2026Updated Sep 11, 2026Source checked Sep 11, 2026First seen by HOL Sep 11, 2026Material review Sep 11, 2026

Upstream Advisory

Key facts

Risk: Unknown severitySource severity not reported
Exploitation: Not marked as known exploited
Affected software: 2 mapped packages or products
Fix availability: Available

Why this deserves its current priority

A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
Linux/Linuxgeneric	>=b9873755a6c8ccfce79094c4dce9efa3ecb1a749 <339f19b9a6171289b0e797deb8bda80b9a1fcc30 \|\| >=b9873755a6c8ccfce79094c4dce9efa3ecb1a749 <29e634a18957acda11383a15ab98a91c4ae9e294 \|\| >=b9873755a6c8ccfce79094c4dce9efa3ecb1a749 <2aa0fb9c96f894a9c179a48e7522ea6705800adf \|\| >=b9873755a6c8ccfce79094c4dce9efa3ecb1a749 <808e530654a5354e6df78863a5d61e4d44e67235	339f19b9a6171289b0e797deb8bda80b9a1fcc30, 29e634a18957acda11383a15ab98a91c4ae9e294, 2aa0fb9c96f894a9c179a48e7522ea6705800adf, 808e530654a5354e6df78863a5d61e4d44e67235
Linux/Linuxgeneric	6.8	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for Linux/Linux, Linux/Linux.
Review the reported fix. Update Linux/Linux to 339f19b9a6171289b0e797deb8bda80b9a1fcc30 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Sep 11, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 11, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Sep 11, 2026

Sources and claim methodology

Upstream source 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.

Quoted source text, attributed separately from HOL analysis.