CVE-2024-26893

CVE-2024-26893 is a medium-severity vulnerability in Linux Linux Kernel with a CVSS 3.x base score of 5.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-415.

Key facts

Description

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.

Frequently asked questions

What is CVE-2024-26893?
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.
How severe is CVE-2024-26893?
CVE-2024-26893 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2024-26893 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (13th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2024-26893?
CVE-2024-26893 affects Linux Linux Kernel. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2024-26893?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2024-26893 have an EU (EUVD) identifier?
Yes. CVE-2024-26893 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2024-24155.
When was CVE-2024-26893 published?
CVE-2024-26893 was published on 2024-04-17 and last updated on 2026-06-17.

References

Affected products (1)

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