High severity · published Sep 11, 2026
CVE-2026-89743
misc: nsm: bound the device-reported response length
7.7
CVSS
0.1%
EPSS
No
On KEV
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 vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
Attack vector
Local
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.1% · higher than 3% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
LI
Linux · Linux
b9873755a6c8ccfce79094c4dce9efa3ecb1a749 before 339f19b9a6171289b0e797deb8bda80b9a1fcc30; b9873755a6c8ccfce79094c4dce9efa3ecb1a749 before 29e634a18957acda11383a15ab98a91c4ae9e294; b9873755a6c8ccfce79094c4dce9efa3ecb1a749 before 2aa0fb9c96f894a9c179a48e7522ea6705800adf; b9873755a6c8ccfce79094c4dce9efa3ecb1a749 before 808e530654a5354e6df78863a5d61e4d44e67235; 6.8 · source: vendor