Linux KernelOperating system · Linux
CVE-2026-53025
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedIn the Linux kernel, the following vulnerability has been resolved: greybus: raw: fix use-after-free on cdev close This addresses a use-after-free bug when a raw bundle is disconnected but its chardev is still opened by an application. When the application releases the cdev, it causes the following panic when init on free is enabled (CONFIG_INIT_ON_FREE_DEFAULT_ON=y): refcount_t: underflow; use-after-free. WARNING: CPU: 0 PID: 139 at lib/refcount.c:28 refcount_warn_saturate+0xd0/0x130 ... Call Trace: <TASK> cdev_put+0x18/0x30 __fput+0x255/0x2a0 __x64_sys_close+0x3d/0x80 do_syscall_64+0xa4/0x290 entry_SYSCALL_64_after_hwframe+0x77/0x7f The cdev is contained in the "gb_raw" structure, which is freed in the disconnect operation. When the cdev is released at a later time, cdev_put gets an address that points to freed memory. To fix this use-after-free, convert the struct device from a pointer to being embedded, that makes the lifetime of the cdev and of this device the same. Then, use cdev_device_add, which guarantees that the device won't be released until all references to the cdev have been released. Finally, delegate the freeing of the structure to the device release function, instead of freeing immediately in the disconnect callback.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceA use-after-free vulnerability exists in the Linux kernel's greybus raw module where the cdev is contained in the gb_raw structure that gets freed during disconnect while applications still hold the chardev open. When the application releases the cdev later, it accesses freed memory causing a refcount underflow panic. The fix embeds the struct device instead of using a pointer, uses cdev_device_add for proper lifetime management, and delegates structure freeing to the device release function.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data
Linux KernelOperating system
>= 4.9, < 7.0.10CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Local
- Complexity
- Low
- Privileges
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Check kernel versionRun `uname -r` or `cat /proc/version` to get the running kernel versionAffected if Kernel version is >= 4.9 and < 7.0.10
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Verify greybus driver is loadedRun `lsmod | grep greybus` or check for greybus modules in /sys/module/Affected if The greybus or greybus_raw module is loaded
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Check if greybus raw device existsLook for /dev/raw/* or check /sys/bus/greybus/devices/ for registered greybus devicesAffected if Any greybus raw character device nodes exist in /dev/
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Confirm raw driver is compiled inCheck kernel config: `cat /boot/config-$(uname -r) | grep -i greybus` or check /proc/config.gzAffected if CONFIG_GREYBUS_RAW=y or CONFIG_GREYBUS=m is set
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Check for open file descriptors to greybus raw deviceRun `lsof | grep -i greybus` or check `/proc/*/fd` for any open handles to /dev/raw/*Affected if An application has an open file descriptor to a greybus raw device while the driver disconnects
A system is affected if it runs a kernel between 4.9 and 7.0.10 with the greybus raw driver loaded and has an active greybus raw character device that could be open during a disconnect event.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scoped7.0.10
Apply the kernel patch which converts the struct device from a pointer to embedded and uses cdev_device_add with proper device release handling to ensure the cdev lifetime matches the device lifetime.
Linux Kernel 7.0.10 or later stable release containing the greybus raw cdev lifetime fix
- Identify the affected kernel version in use (must be >= 4.9 and < 7.0.10)
- Apply the upstream kernel patch for the greybus raw driver that converts struct device from a pointer to embedded, uses cdev_device_add instead of cdev_add, and delegates structure freeing to the device release function
- Verify the patch is applied correctly by reviewing the changed files in drivers/staging/greybus/raw.c
- Rebuild the kernel with the patched greybus driver
- Deploy the updated kernel and verify the greybus raw functionality works correctly without use-after-free errors
- Enable kernel memory debugging features (like CONFIG_KASAN or similar) temporarily to confirm the vulnerability is resolved
Generated from the published advisory — verify against the referenced sources before acting.
Fix this in Linux Kernel
Scoped from the published advisory
- Consultation2.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-53025 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-53025 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
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