CVE-2026-89743: Linux kernel · misc: nsm: bound the device-reported response length
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.7 High.
Data as of 28 Oct 2026, 01:01 UTC
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 11 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-gkepkg:deb/ubuntu/linux-gke?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
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.
References
- ubuntu.com/security/CVE-2026-89743 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-89743 (opens in a new tab)
- git.kernel.org/linus/808e530654a5354e6df78863a5d61e4d44e67235 (opens in a new tab)
- git.kernel.org/stable/c/29e634a18957acda11383a15ab98a91c4ae9e294 (opens in a new tab)
- git.kernel.org/stable/c/2aa0fb9c96f894a9c179a48e7522ea6705800adf (opens in a new tab)
- git.kernel.org/stable/c/339f19b9a6171289b0e797deb8bda80b9a1fcc30 (opens in a new tab)
- git.kernel.org/stable/c/808e530654a5354e6df78863a5d61e4d44e67235 (opens in a new tab)