# CVE-2026-31485: spi: spi-fsl-lpspi: fix teardown order issue (UAF)

Status: published. Published: 2026-04-22. Updated: 2026-11-05.

In the Linux kernel, the following vulnerability has been resolved:

spi: spi-fsl-lpspi: fix teardown order issue (UAF)

There is a teardown order issue in the driver. The SPI controller is
registered using devm_spi_register_controller(), which delays
unregistration of the SPI controller until after the fsl_lpspi_remove()
function returns.

As the fsl_lpspi_remove() function synchronously tears down the DMA
channels, a running SPI transfer triggers the following NULL pointer
dereference due to use after free:

| fsl_lpspi 42550000.spi: I/O Error in DMA RX
| Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000
[...]
| Call trace:
|  fsl_lpspi_dma_transfer+0x260/0x340 [spi_fsl_lpspi]
|  fsl_lpspi_transfer_one+0x198/0x448 [spi_fsl_lpspi]
|  spi_transfer_one_message+0x49c/0x7c8
|  __spi_pump_transfer_message+0x120/0x420
|  __spi_sync+0x2c4/0x520
|  spi_sync+0x34/0x60
|  spidev_message+0x20c/0x378 [spidev]
|  spidev_ioctl+0x398/0x750 [spidev]
[...]

Switch from devm_spi_register_controller() to spi_register_controller() in
fsl_lpspi_probe() and add the corresponding spi_unregister_controller() in
fsl_lpspi_remove().

## Remediation

No remediation reported in collected sources

## Affected products and versions

- Linux / Linux: ≥ 5314987de5e5f5e38436ef4a69328bc472bbd63e; < fbe6f40caeebb0b1ea9dfedc259124c1d3cda7a6 (affected, git); ≥ 5314987de5e5f5e38436ef4a69328bc472bbd63e; < ca4483f36ac1b62e69f8b182c5b8f059e0abecfb (affected, git); ≥ 5314987de5e5f5e38436ef4a69328bc472bbd63e; < e3fd54f8b0317fbccc103961ddd660f2a32dcf0b (affected, git); ≥ 5314987de5e5f5e38436ef4a69328bc472bbd63e; < adb25339b66112393fd6892ceff926765feb5b86 (affected, git); ≥ 5314987de5e5f5e38436ef4a69328bc472bbd63e; < d5d01f24bc6fbde40b4e567ef9160194b61267bc (affected, git); ≥ 5314987de5e5f5e38436ef4a69328bc472bbd63e; < e89e2b97253c124d37bf88e96e5e8ce5c3aeeec3 (affected, git); ≥ 5314987de5e5f5e38436ef4a69328bc472bbd63e; < 15650dfbaeeb14bcaaf053b93cf631db8d465300 (affected, git); ≥ 5314987de5e5f5e38436ef4a69328bc472bbd63e; < b341c1176f2e001b3adf0b47154fc31589f7410e (affected, git). Source: CNA: Linux
- Linux / Linux: 4.10 (affected); ≥ 0; < 4.10 (unaffected, semver); ≥ 5.10.253; ≤ 5.10.* (unaffected, semver); ≥ 5.15.203; ≤ 5.15.* (unaffected, semver); ≥ 6.1.168; ≤ 6.1.* (unaffected, semver); ≥ 6.6.131; ≤ 6.6.* (unaffected, semver); ≥ 6.12.80; ≤ 6.12.* (unaffected, semver); ≥ 6.18.21; ≤ 6.18.* (unaffected, semver); ≥ 6.19.11; ≤ 6.19.* (unaffected, semver); ≥ 7.0; ≤ * (unaffected, original_commit_for_fix). Source: CNA: Linux
- Siemens / SIMATIC S7-1500 CPU 1518-4 PN/DP MFP: ≥ V3.1.6; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIMATIC S7-1500 CPU 1518-4 PN/DP MFP: ≥ V3.1.5; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIMATIC S7-1500 CPU 1518-4 PN/DP MFP: ≥ V3.1.7; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP: ≥ V3.1.6; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP: ≥ V3.1.5; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP: ≥ V3.1.7; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIPLUS S7-1500 CPU 1518-4 PN/DP MFP: ≥ V3.1.6; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIPLUS S7-1500 CPU 1518-4 PN/DP MFP: ≥ V3.1.5; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIPLUS S7-1500 CPU 1518-4 PN/DP MFP: ≥ V3.1.7; < * (affected, custom). Source: ADP: siemens-SADP

## Severity and prioritization

- CISA KEV: No listing in collected sources

- EPSS: 0.13% as of 2026-11-05; percentile 2.74%

- SSVC: exploitation none; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: Not reported

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://git.kernel.org/stable/c/fbe6f40caeebb0b1ea9dfedc259124c1d3cda7a6 (CNA: Linux)

- https://git.kernel.org/stable/c/ca4483f36ac1b62e69f8b182c5b8f059e0abecfb (CNA: Linux)

- https://git.kernel.org/stable/c/e3fd54f8b0317fbccc103961ddd660f2a32dcf0b (CNA: Linux)

- https://git.kernel.org/stable/c/adb25339b66112393fd6892ceff926765feb5b86 (CNA: Linux)

- https://git.kernel.org/stable/c/d5d01f24bc6fbde40b4e567ef9160194b61267bc (CNA: Linux)

- https://git.kernel.org/stable/c/e89e2b97253c124d37bf88e96e5e8ce5c3aeeec3 (CNA: Linux)

- https://git.kernel.org/stable/c/15650dfbaeeb14bcaaf053b93cf631db8d465300 (CNA: Linux)

- https://git.kernel.org/stable/c/b341c1176f2e001b3adf0b47154fc31589f7410e (CNA: Linux)

- https://cert-portal.siemens.com/productcert/html/ssa-082556.html (ADP: siemens-SADP)

- https://cert-portal.siemens.com/productcert/html/ssa-019113.html (ADP: siemens-SADP)

- https://cert-portal.siemens.com/productcert/html/ssa-457936.html (ADP: siemens-SADP)

## Provenance

- CNA: Linux: https://www.cve.org/CVERecord?id=CVE-2026-31485; retrieved 2026-11-05; source updated 2026-11-05

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-31485; retrieved 2026-11-05; source updated Not reported

Revision: 04e9889ad2cc5ea74b4efbdfd6cafa08f3facf4faece8e0494a55b15ba5e6754

Canonical: https://y2.dev/cve/CVE-2026-31485

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