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CVE Record

CVE-2024-26893: firmware: arm_scmi: Fix double free in SMC transport cleanup path

In the Linux kernel, the following vulnerability has been resolved: firmware: arm_scmi: Fix double free in SMC transport cleanup path When the generic SCMI code tears down a channel, it calls the chan_free callback function, defined by each transport. Since multiple protocols might share the same transport_info member, chan_free() might want to clean up the same member multiple times within the given SCMI transport implementation. In this case, it is SMC transport. This will lead to a NULL pointer dereference at the second time: | scmi_protocol scmi_dev.1: Enabled polling mode TX channel - prot_id:16 | arm-scmi firmware:scmi: SCMI Notifications - Core Enabled. | arm-scmi firmware:scmi: unable to communicate with SCMI | Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000 | Mem abort info: | ESR = 0x0000000096000004 | EC = 0x25: DABT (current EL), IL = 32 bits | SET = 0, FnV = 0 | EA = 0, S1PTW = 0 | FSC = 0x04: level 0 translation fault | Data abort info: | ISV = 0, ISS = 0x00000004, ISS2 = 0x00000000 | CM = 0, WnR = 0, TnD = 0, TagAccess = 0 | GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0 | user pgtable: 4k pages, 48-bit VAs, pgdp=0000000881ef8000 | [0000000000000000] pgd=0000000000000000, p4d=0000000000000000 | Internal error: Oops: 0000000096000004 [#1] PREEMPT SMP | Modules linked in: | CPU: 4 PID: 1 Comm: swapper/0 Not tainted 6.7.0-rc2-00124-g455ef3d016c9-dirty #793 | Hardware name: FVP Base RevC (DT) | pstate: 61400009 (nZCv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--) | pc : smc_chan_free+0x3c/0x6c | lr : smc_chan_free+0x3c/0x6c | Call trace: | smc_chan_free+0x3c/0x6c | idr_for_each+0x68/0xf8 | scmi_cleanup_channels.isra.0+0x2c/0x58 | scmi_probe+0x434/0x734 | platform_probe+0x68/0xd8 | really_probe+0x110/0x27c | __driver_probe_device+0x78/0x12c | driver_probe_device+0x3c/0x118 | __driver_attach+0x74/0x128 | bus_for_each_dev+0x78/0xe0 | driver_attach+0x24/0x30 | bus_add_driver+0xe4/0x1e8 | driver_register+0x60/0x128 | __platform_driver_register+0x28/0x34 | scmi_driver_init+0x84/0xc0 | do_one_initcall+0x78/0x33c | kernel_init_freeable+0x2b8/0x51c | kernel_init+0x24/0x130 | ret_from_fork+0x10/0x20 | Code: f0004701 910a0021 aa1403e5 97b91c70 (b9400280) | ---[ end trace 0000000000000000 ]--- Simply check for the struct pointer being NULL before trying to access its members, to avoid this situation. This was found when a transport doesn't really work (for instance no SMC service), the probe routines then tries to clean up, and triggers a crash.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

CVE-2024-26893 is a Linux kernel crash bug in the ARM SCMI SMC transport cleanup path. If SCMI setup fails, such as when no SMC service is available, cleanup can free shared transport data twice and crash the kernel. The public record does not show active exploitation.

Executive priority

Treat this as a targeted reliability risk for ARM Linux platforms, not a broad internet-facing emergency. Patch through normal kernel maintenance, with higher priority for appliances or embedded systems where a boot-time kernel crash would disrupt service.

Technical view

The generic SCMI teardown calls each transport's chan_free callback. In the SMC transport, multiple protocols can share transport_info, so cleanup may access already-freed or NULL state. The fix adds a NULL check before member access to prevent the second cleanup path from dereferencing NULL.

Likely exposure

Exposure is most relevant to ARM systems using Linux kernel SCMI firmware support with the SMC transport. The CVE record lists Linux as affected and includes stable kernel fix references. Downstream distro and device firmware exposure needs vendor confirmation.

Exploitation context

The provided sources describe a kernel NULL pointer dereference during SCMI probe cleanup when the transport does not work. KEV is false, and no cited source in the bundle reports active exploitation or a public exploit.

Researcher notes

Evidence is limited to the CVE description and Linux stable commit references. The source indicates a cleanup-path double free leading to NULL dereference, triggered when SCMI SMC transport probing fails. No CVSS, CWE, exploitability analysis, or downstream vendor matrix is provided.

Mitigation direction

  • Review Linux vendor advisories for CVE-2024-26893 applicability.
  • Update to a kernel build containing the referenced stable SCMI SMC fix.
  • Prioritize ARM platforms using SCMI over SMC transport.
  • Track downstream distro or device firmware kernel backports.
  • Avoid direct wrangler-style assumptions; follow vendor kernel packaging guidance.

Validation and detection

  • Inventory ARM Linux systems and kernel versions.
  • Check kernel changelogs for the referenced SCMI SMC cleanup fix.
  • Confirm whether SCMI SMC transport is enabled on target platforms.
  • Review boot or probe logs for ARM SCMI initialization failures.
  • Validate patched systems no longer crash during failed SCMI probe cleanup.
Prepared
Confidence
medium
Sources
7

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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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
6Source 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

CISA-ADPCISA ADP Vulnrichment
other:ssvc
CVECVE Program Container

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux1dc6558062dadfabd2fb3bd885fa6e92ec7196f2, 1dc6558062dadfabd2fb3bd885fa6e92ec7196f2, 1dc6558062dadfabd2fb3bd885fa6e92ec7196f2, 1dc6558062dadfabd2fb3bd885fa6e92ec7196f2, 1dc6558062dadfabd2fb3bd885fa6e92ec7196f2unaffected
LinuxLinux5.8, 0, 6.1.83, 6.6.23, 6.7.11, 6.8.2, 6.9affected
Weakness

CWE details

No CWE listed

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