# CVE-2026-72142: i2c: imx: fix locked bus on SMBus block-read of 0 (atomic)

Status: published. Published: 2026-08-15. Updated: 2026-11-06.

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

i2c: imx: fix locked bus on SMBus block-read of 0 (atomic)

SMBus 3.1 6.5.7 allows a Block Read byte count of 0, but the atomic
(polling) path rejects it as -EPROTO. Worse, it returns without a
NACK+STOP: the next receive cycle has already started, so the target
keeps holding SDA and the bus stays stuck until a power cycle for
this i2c controller.

Reading I2DR to obtain the count likewise arms the next byte on the
count > I2C_SMBUS_BLOCK_MAX path, which also returned -EPROTO directly
and left the bus held.

Handle both: NACK the in-flight dummy byte (TXAK) and extend msgs->len so
the existing last-byte handling emits STOP; the dummy byte is discarded.
A count of 0 is a valid empty block read; a count above
I2C_SMBUS_BLOCK_MAX is still reported as -EPROTO, but only after the bus
has been released.

The interrupt-driven path has the same flaw from a later commit and is
fixed separately, as it carries a different Fixes: tag and stable range.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- Linux / Linux: ≥ 8e8782c71595a5ad29e234ce6b3d2fce787fb07a; < 0f29df3c3d607a9dbc14aed0e45504ced4d2e7ec (affected, git); ≥ 8e8782c71595a5ad29e234ce6b3d2fce787fb07a; < 38d4947431b2410850409fda016b2ac9f640a4dd (affected, git); ≥ 8e8782c71595a5ad29e234ce6b3d2fce787fb07a; < e3e8b02d4773cfc5ad561d2e5505efde36c6927a (affected, git); ≥ 8e8782c71595a5ad29e234ce6b3d2fce787fb07a; < 016ef0f6ca4bc9bf0330ac41bd2ea349759643e3 (affected, git); ≥ 8e8782c71595a5ad29e234ce6b3d2fce787fb07a; < c882e8cc68fb993700dc21fd6e754001e6297934 (affected, git); ≥ 8e8782c71595a5ad29e234ce6b3d2fce787fb07a; < 6d2c973926d0612360693bc559be2ffde836151b (affected, git); ≥ 8e8782c71595a5ad29e234ce6b3d2fce787fb07a; < 60ed00d46616a9232e42ea7a3e3c0273d7cf7543 (affected, git); ≥ 8e8782c71595a5ad29e234ce6b3d2fce787fb07a; < cb2fc37857693b55909fb77dc2c87cfbc1cdc476 (affected, git). Source: CNA: Linux
- Linux / Linux: 3.16 (affected); ≥ 0; < 3.16 (unaffected, semver); ≥ 5.10.266; ≤ 5.10.* (unaffected, semver); ≥ 5.15.217; ≤ 5.15.* (unaffected, semver); ≥ 6.1.184; ≤ 6.1.* (unaffected, semver); ≥ 6.6.148; ≤ 6.6.* (unaffected, semver); ≥ 6.12.101; ≤ 6.12.* (unaffected, semver); ≥ 6.18.40; ≤ 6.18.* (unaffected, semver); ≥ 7.1.5; ≤ 7.1.* (unaffected, semver); ≥ 7.2; ≤ * (unaffected, original_commit_for_fix). Source: CNA: Linux

## Severity and prioritization

- CISA KEV: No listing in collected sources

- EPSS: 0.22% as of 2026-11-06; percentile 12.13%

- 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/0f29df3c3d607a9dbc14aed0e45504ced4d2e7ec (CNA: Linux)

- https://git.kernel.org/stable/c/38d4947431b2410850409fda016b2ac9f640a4dd (CNA: Linux)

- https://git.kernel.org/stable/c/e3e8b02d4773cfc5ad561d2e5505efde36c6927a (CNA: Linux)

- https://git.kernel.org/stable/c/016ef0f6ca4bc9bf0330ac41bd2ea349759643e3 (CNA: Linux)

- https://git.kernel.org/stable/c/c882e8cc68fb993700dc21fd6e754001e6297934 (CNA: Linux)

- https://git.kernel.org/stable/c/6d2c973926d0612360693bc559be2ffde836151b (CNA: Linux)

- https://git.kernel.org/stable/c/60ed00d46616a9232e42ea7a3e3c0273d7cf7543 (CNA: Linux)

- https://git.kernel.org/stable/c/cb2fc37857693b55909fb77dc2c87cfbc1cdc476 (CNA: Linux)

- https://git.kernel.org/stable/c/016ef0f6ca4bc9bf0330ac41bd2ea349759643e3 (416baaa9-dc9f-4396-8d5f-8c081fb06d67)

- https://git.kernel.org/stable/c/0f29df3c3d607a9dbc14aed0e45504ced4d2e7ec (416baaa9-dc9f-4396-8d5f-8c081fb06d67)

- https://git.kernel.org/stable/c/38d4947431b2410850409fda016b2ac9f640a4dd (416baaa9-dc9f-4396-8d5f-8c081fb06d67)

- https://git.kernel.org/stable/c/60ed00d46616a9232e42ea7a3e3c0273d7cf7543 (416baaa9-dc9f-4396-8d5f-8c081fb06d67)

- https://git.kernel.org/stable/c/6d2c973926d0612360693bc559be2ffde836151b (416baaa9-dc9f-4396-8d5f-8c081fb06d67)

- https://git.kernel.org/stable/c/c882e8cc68fb993700dc21fd6e754001e6297934 (416baaa9-dc9f-4396-8d5f-8c081fb06d67)

- https://git.kernel.org/stable/c/cb2fc37857693b55909fb77dc2c87cfbc1cdc476 (416baaa9-dc9f-4396-8d5f-8c081fb06d67)

- https://git.kernel.org/stable/c/e3e8b02d4773cfc5ad561d2e5505efde36c6927a (416baaa9-dc9f-4396-8d5f-8c081fb06d67)

## Provenance

- CNA: Linux: https://www.cve.org/CVERecord?id=CVE-2026-72142; retrieved 2026-11-06; source updated 2026-11-06

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-72142; retrieved 2026-11-06; source updated 2026-11-06

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-72142; retrieved 2026-11-06; source updated Not reported

Revision: 648857b0514ba6beca1a17fd4d1c8626e58e9f4fb0d132028bf578ab88b236a6

Canonical: https://y2.dev/cve/CVE-2026-72142

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