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CVE Record

CVE-2022-48838: usb: gadget: Fix use-after-free bug by not setting udc->dev.driver

In the Linux kernel, the following vulnerability has been resolved: usb: gadget: Fix use-after-free bug by not setting udc->dev.driver The syzbot fuzzer found a use-after-free bug: BUG: KASAN: use-after-free in dev_uevent+0x712/0x780 drivers/base/core.c:2320 Read of size 8 at addr ffff88802b934098 by task udevd/3689 CPU: 2 PID: 3689 Comm: udevd Not tainted 5.17.0-rc4-syzkaller-00229-g4f12b742eb2b #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014 Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 print_address_description.constprop.0.cold+0x8d/0x303 mm/kasan/report.c:255 __kasan_report mm/kasan/report.c:442 [inline] kasan_report.cold+0x83/0xdf mm/kasan/report.c:459 dev_uevent+0x712/0x780 drivers/base/core.c:2320 uevent_show+0x1b8/0x380 drivers/base/core.c:2391 dev_attr_show+0x4b/0x90 drivers/base/core.c:2094 Although the bug manifested in the driver core, the real cause was a race with the gadget core. dev_uevent() does: if (dev->driver) add_uevent_var(env, "DRIVER=%s", dev->driver->name); and between the test and the dereference of dev->driver, the gadget core sets dev->driver to NULL. The race wouldn't occur if the gadget core registered its devices on a real bus, using the standard synchronization techniques of the driver core. However, it's not necessary to make such a large change in order to fix this bug; all we need to do is make sure that udc->dev.driver is always NULL. In fact, there is no reason for udc->dev.driver ever to be set to anything, let alone to the value it currently gets: the address of the gadget's driver. After all, a gadget driver only knows how to manage a gadget, not how to manage a UDC. This patch simply removes the statements in the gadget core that touch udc->dev.driver.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

CVE-2022-48838 is a Linux kernel use-after-free bug in USB gadget handling. A race can leave the kernel reading a driver pointer after it was cleared. The public record shows it was found by syzbot and fixed in stable kernel commits, but does not provide CVSS, confirmed exploitability, or impact beyond the kernel memory-safety fault.

Executive priority

Track and remediate through normal kernel patch governance, with higher priority for embedded, appliance, or USB device-mode deployments. The public evidence does not support emergency treatment, but kernel memory-safety bugs should not be left unpatched.

Technical view

The issue is in the USB gadget core setting udc->dev.driver. dev_uevent checks dev->driver and later dereferences it; a race can set it to NULL between those operations, producing a KASAN use-after-free report in driver core code. The fix removes gadget-core writes to udc->dev.driver so it remains NULL.

Likely exposure

Exposure is most relevant to Linux systems with affected kernel versions and USB gadget or UDC functionality. Downstream distribution exposure cannot be concluded from the bundle alone; map your running kernel package to vendor advisories and the listed stable commits.

Exploitation context

The source bundle reports syzbot discovery and a kernel crash-style memory-safety bug. It does not cite active exploitation, public weaponization, KEV listing, privilege requirements, or a complete attack path. Treat exploit status as unconfirmed.

Researcher notes

Evidence supports a race-driven use-after-free in Linux USB gadget driver-state handling, fixed by keeping udc->dev.driver unset. The bundle lacks CVSS, CWE, exploitability analysis, and downstream distro mapping, so validation should focus on code lineage and vendor kernel status.

Mitigation direction

  • Update to a vendor kernel containing the referenced stable fixes.
  • Check distribution advisories for package-specific fixed versions.
  • Prioritize systems using USB gadget or UDC features.
  • If unsupported, consider disabling unnecessary USB gadget functionality under vendor guidance.

Validation and detection

  • Inventory Linux kernel versions across servers, appliances, and embedded devices.
  • Identify systems with USB gadget or UDC support enabled.
  • Compare kernel builds against vendor advisories and referenced stable commits.
  • Review kernel logs for related KASAN or uevent crash reports.
Prepared
Confidence
medium
Sources
10

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

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CVE-2022-48838 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
3Timeline events
2ADP providers
9Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: noTechnical Impact: partial

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CVECVE Program Container
CISA-ADPCISA ADP Vulnrichment
other:ssvc

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux2ccea03a8f7ec93641791f2760d7cdc6cab6205f, 2ccea03a8f7ec93641791f2760d7cdc6cab6205f, 2ccea03a8f7ec93641791f2760d7cdc6cab6205f, 2ccea03a8f7ec93641791f2760d7cdc6cab6205f, 2ccea03a8f7ec93641791f2760d7cdc6cab6205f, 2ccea03a8f7ec93641791f2760d7cdc6cab6205f, 2ccea03a8f7ec93641791f2760d7cdc6cab6205f, 2ccea03a8f7ec93641791f2760d7cdc6cab6205funaffected
LinuxLinux3.1, 0, 4.9.308, 4.14.273, 4.19.236, 5.4.187, 5.10.108, 5.15.31, 5.16.17, 5.17affected
Weakness

CWE details

No CWE listed

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