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CVE Record

CVE-2025-21943: gpio: aggregator: protect driver attr handlers against module unload

In the Linux kernel, the following vulnerability has been resolved: gpio: aggregator: protect driver attr handlers against module unload Both new_device_store and delete_device_store touch module global resources (e.g. gpio_aggregator_lock). To prevent race conditions with module unload, a reference needs to be held. Add try_module_get() in these handlers. For new_device_store, this eliminates what appears to be the most dangerous scenario: if an id is allocated from gpio_aggregator_idr but platform_device_register has not yet been called or completed, a concurrent module unload could fail to unregister/delete the device, leaving behind a dangling platform device/GPIO forwarder. This can result in various issues. The following simple reproducer demonstrates these problems: #!/bin/bash while :; do # note: whether 'gpiochip0 0' exists or not does not matter. echo 'gpiochip0 0' > /sys/bus/platform/drivers/gpio-aggregator/new_device done & while :; do modprobe gpio-aggregator modprobe -r gpio-aggregator done & wait Starting with the following warning, several kinds of warnings will appear and the system may become unstable: ------------[ cut here ]------------ list_del corruption, ffff888103e2e980->next is LIST_POISON1 (dead000000000100) WARNING: CPU: 1 PID: 1327 at lib/list_debug.c:56 __list_del_entry_valid_or_report+0xa3/0x120 [...] RIP: 0010:__list_del_entry_valid_or_report+0xa3/0x120 [...] Call Trace: <TASK> ? __list_del_entry_valid_or_report+0xa3/0x120 ? __warn.cold+0x93/0xf2 ? __list_del_entry_valid_or_report+0xa3/0x120 ? report_bug+0xe6/0x170 ? __irq_work_queue_local+0x39/0xe0 ? handle_bug+0x58/0x90 ? exc_invalid_op+0x13/0x60 ? asm_exc_invalid_op+0x16/0x20 ? __list_del_entry_valid_or_report+0xa3/0x120 gpiod_remove_lookup_table+0x22/0x60 new_device_store+0x315/0x350 [gpio_aggregator] kernfs_fop_write_iter+0x137/0x1f0 vfs_write+0x262/0x430 ksys_write+0x60/0xd0 do_syscall_64+0x6c/0x180 entry_SYSCALL_64_after_hwframe+0x76/0x7e [...] </TASK> ---[ end trace 0000000000000000 ]---

MediumCVSS 4.7Not KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

CVE-2025-21943 is a Linux kernel reliability flaw in the GPIO aggregator driver. A local user with limited privileges could trigger a timing race while the module is loading or unloading, potentially making the system unstable. The disclosed impact is availability, not data theft or privilege escalation.

Executive priority

Treat this as a routine but real kernel stability risk. It is not documented as remotely exploitable or actively exploited, but shared systems and appliances with local user access should receive kernel updates through normal vulnerability maintenance windows.

Technical view

The issue is a CWE-362 race in gpio-aggregator driver attribute handlers. new_device_store and delete_device_store accessed module-global resources during concurrent module unload without holding a module reference. The fix adds try_module_get to protect those handlers. Reported outcomes include dangling platform device/GPIO forwarder state, list corruption warnings, and possible instability.

Likely exposure

Exposure is most relevant to Linux systems running affected kernel builds where gpio-aggregator is present and reachable. The CVE record lists affected Linux versions including 5.8 and several stable branch points through 6.14. Systems without this driver loaded or accessible have lower practical exposure.

Exploitation context

The CVSS vector is local, high complexity, low privileges, no user interaction, with high availability impact. The source includes a race reproducer, but KEV is false and the provided sources do not state active exploitation in the wild.

Researcher notes

The important boundary is availability. The provided evidence supports a local race causing corruption and instability, not confidentiality loss, integrity compromise, or privilege escalation. Confirm branch-specific fix status from kernel stable commits or distro advisories before declaring a host remediated.

Mitigation direction

  • Update to a kernel containing the referenced gpio-aggregator fixes.
  • Follow Linux distribution advisories for backported kernel packages.
  • Restrict unnecessary local access to gpio-aggregator sysfs driver controls.
  • Disable or avoid loading gpio-aggregator where it is not operationally required.
  • Prioritize systems where untrusted local users can access kernel driver interfaces.

Validation and detection

  • Inventory kernel versions against the CVE affected version list.
  • Check whether gpio-aggregator is built, loadable, or currently loaded.
  • Confirm installed kernel packages include the vendor backport or stable fix.
  • Review system logs for related list corruption or gpio-aggregator instability warnings.
  • Validate local access controls around platform driver sysfs attributes.
Prepared
Confidence
high
Sources
11

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

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

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cwe · low confidence lookup

CWE-362: Exact CWE lookup

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cve · low confidence lookup

CVE-2025-21943 mapping review

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Vulnerability profileCVE Program record
Severity
Medium
CVSS
4.7 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H

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.

1CVSS vectors
3Timeline events
2ADP providers
10Source links

SSVC decision data

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

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
4.7CVSS 3.1MediumCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H13.6CISA-ADP

Vulnerability scoring details

Base CVSS 3.1 score

4.7Medium
CVSS 3.1 vector shape for CVE-2025-21943Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

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

CISA-ADPCISA ADP Vulnrichment
cvssV3_1other:ssvc
CVECVE Program Container

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux828546e24280f721350a7a0dcc92416e917b4382, 828546e24280f721350a7a0dcc92416e917b4382, 828546e24280f721350a7a0dcc92416e917b4382, 828546e24280f721350a7a0dcc92416e917b4382, 828546e24280f721350a7a0dcc92416e917b4382, 828546e24280f721350a7a0dcc92416e917b4382, 828546e24280f721350a7a0dcc92416e917b4382unaffected
LinuxLinux5.8, 0, 5.10.235, 5.15.179, 6.1.131, 6.6.83, 6.12.19, 6.13.7, 6.14affected
Weakness

CWE details

CWE-362

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.

CWE-362 · source CWE mapping

Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

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