CVE-2026-74681: Linux kernel · usb: misc: usbio: check ibuf_len against rxbuf_len in bulk msg
Affects Linux kernelSource GCVE Database
Not known to be exploited.
Data as of 26 Oct 2026, 14:05 UTC
Rated by Threat Radar · CVSS not yet scored by NVD
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 10% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Exploitation evidence
Disclosed: evidence found.
CVE published 22 Aug 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.
AI-suggested
A fix has been implemented in the Linux kernel to correct the buffer size check in usbio_bulk_msg(). Users should update to the kernel version that includes this fix once available. Patch status is not explicitly confirmed; check the Linux kernel vendor advisory or source repository for the exact fixed version and apply the update accordingly.
Description
In the Linux kernel, the following vulnerability has been resolved: usb: misc: usbio: check ibuf_len against rxbuf_len in bulk msg ibuf_len is the bulk IN (receive) buffer size, but the EMSGSIZE check in usbio_bulk_msg() compares it against txbuf_len — the bulk OUT endpoint size. Both are taken independently from different endpoints in usbio_probe(), so the check is wrong when they differ. Use rxbuf_len for the IN direction. This matches the buffer that actually holds the response data.
References
- nvd.nist.gov/vuln/detail/CVE-2026-74681 (opens in a new tab)
- git.kernel.org/stable/c/7e22c9f79b200672f3e477421b6c9050d8cf70a5 (opens in a new tab)
- git.kernel.org/stable/c/9ad0164f78b66b0b5eca3a5748cc94dd87e28124 (opens in a new tab)
- git.kernel.org/stable/c/ebfd1e82ab0a6d26efd9bdd89de899215851f5bf (opens in a new tab)
- ubuntu.com/security/CVE-2026-74681 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-74681 (opens in a new tab)
- git.kernel.org/linus/7e22c9f79b200672f3e477421b6c9050d8cf70a5 (opens in a new tab)