VulnerabilityPublished 25 Jul 2026Updated 6 Nov 2026

CVE-2026-64376: Linux kernel · firmware_loader: fix device reference leak in firmware_upload_register()

Affects Linux kernelSource CVE Database V5

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Not known to be exploited · fixed in 517676ec7dfca064e08f94007a4abd21969de0a0 : update Linux kernel when convenient.

Data as of 6 Nov 2026, 17:04 UTC

Severity

Unrated

Rated by Threat Radar · No CVSS score from NVD or the CNA

Thin evidence

One scorer or none

Exploitation: No evidence of active exploitation and no public proof of concept
Automatable: Attackers cannot reliably automate steps 1–4 of the kill chain
Technical impact: Limited control over the software or limited information exposure

CISA SSVC assessment, 2026-11-06.

Patch

Available – fixed in 517676ec7dfca064e08f94007a4abd21969de0a0, 15432f19562fdb9199cce6d9fc24db12c71ed574, 2619b47a0c8114eef980a56ade7e3ef4b58eb384 +3

Exploitation evidence

Disclosed: evidence found.
CVE published 25 Jul 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: 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 6 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 97730bbb242cde22b7140acd202ffd88823886c9, < 517676ec7dfca064e08f94007a4abd21969de0a0	Fixed in 517676ec7dfca064e08f94007a4abd21969de0a0
LinuxLinux	Affected ≥ 97730bbb242cde22b7140acd202ffd88823886c9, < 15432f19562fdb9199cce6d9fc24db12c71ed574	Fixed in 15432f19562fdb9199cce6d9fc24db12c71ed574
LinuxLinux	Affected ≥ 97730bbb242cde22b7140acd202ffd88823886c9, < 2619b47a0c8114eef980a56ade7e3ef4b58eb384	Fixed in 2619b47a0c8114eef980a56ade7e3ef4b58eb384
LinuxLinux	Affected ≥ 97730bbb242cde22b7140acd202ffd88823886c9, < 896df22ee57648b0c505bd76ddbc6b2341834696	Fixed in 896df22ee57648b0c505bd76ddbc6b2341834696
LinuxLinux	Affected ≥ 97730bbb242cde22b7140acd202ffd88823886c9, < 92f41769e5fd16bcd9ba97500d0517332e0a5b45	Fixed in 92f41769e5fd16bcd9ba97500d0517332e0a5b45
LinuxLinux	Affected ≥ 97730bbb242cde22b7140acd202ffd88823886c9, < 46d403da376a8b7c1187193294953816e1a8d7fe	Fixed in 46d403da376a8b7c1187193294953816e1a8d7fe

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

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