CVE-2026-64376: Linux kernel · firmware_loader: fix device reference leak in firmware_upload_register()
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 5.5 Medium · fixed in 7.0.0-1012.12~24.04.1 : update Linux kernel when convenient.
Data as of 26 Oct 2026, 17:16 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 2% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 7.0.0-1012.12~24.04.1, 7.0.0-1011.11~24.04.1, 7.0.0-31.31~24.04.1 +7
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 25 Jul 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
Upgrade to a fixed release listed under Affected software.
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 patch is available and should be applied by updating to the fixed linux-hwe-edge kernel versions as provided by the Ubuntu security advisories USN-8726-1 and USN-8727-1. After applying the update, a system reboot is required. Due to an ABI change, third-party kernel modules must be recompiled and reinstalled. No additional mitigation actions are indicated by the vendor.
Description
In the Linux kernel, the following vulnerability has been resolved: firmware_loader: fix device reference leak in firmware_upload_register() firmware_upload_register() -> fw_create_instance() -> device_initialize() After fw_create_instance() succeeds, the lifetime of the embedded struct device is expected to be managed through the device core reference counting, since fw_create_instance() has already called device_initialize(). In firmware_upload_register(), if alloc_lookup_fw_priv() fails after fw_create_instance() succeeds, the code reaches free_fw_sysfs and frees fw_sysfs directly instead of releasing the device reference with put_device(). This may leave the reference count of the embedded struct device unbalanced, resulting in a refcount leak. The issue was identified by a static analysis tool I developed and confirmed by manual review. Fix this by using put_device(fw_dev) in the failure path and letting fw_dev_release() handle the final cleanup, instead of freeing the instance directly from the error path.
References
- nvd.nist.gov/vuln/detail/CVE-2026-64376 (opens in a new tab)
- git.kernel.org/stable/c/15432f19562fdb9199cce6d9fc24db12c71ed574 (opens in a new tab)
- git.kernel.org/stable/c/2619b47a0c8114eef980a56ade7e3ef4b58eb384 (opens in a new tab)
- git.kernel.org/stable/c/46d403da376a8b7c1187193294953816e1a8d7fe (opens in a new tab)
- git.kernel.org/stable/c/517676ec7dfca064e08f94007a4abd21969de0a0 (opens in a new tab)
- git.kernel.org/stable/c/896df22ee57648b0c505bd76ddbc6b2341834696 (opens in a new tab)
- git.kernel.org/stable/c/92f41769e5fd16bcd9ba97500d0517332e0a5b45 (opens in a new tab)
- ubuntu.com/security/CVE-2026-64376 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-64376 (opens in a new tab)
- git.kernel.org/linus/896df22ee57648b0c505bd76ddbc6b2341834696 (opens in a new tab)
- ubuntu.com/security/notices/USN-8726-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8727-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8728-1 (opens in a new tab)