i2c: imx: fix locked bus on SMBus block-read of 0 (atomic)
Published Aug 15, 2026
5.5
MEDIUMCVSS 3.1
EPSS 0.22%
Description
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.
Affected products
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- Version StatusaffectedConstraints
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- Version
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- Version 3.16StatusaffectedConstraints-
- Version 0StatusunaffectedConstraints<3.16
- Version 5.10.266StatusunaffectedConstraints<=5.10.*
- Version 5.15.217StatusunaffectedConstraints<=5.15.*
- Version 6.1.184StatusunaffectedConstraints<=6.1.*
- Version 6.12.101StatusunaffectedConstraints<=6.12.*
- Version 6.18.40StatusunaffectedConstraints<=6.18.*
- Version 6.6.148StatusunaffectedConstraints<=6.6.*
- Version 7.1.5StatusunaffectedConstraints<=7.1.*
- Version 7.2StatusunaffectedConstraints<=*
- Version
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | |||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Linux | Linux | unaffected |
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| Linux | Linux | affected |
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No data.
No data.
Red Hat Enterprise Linux 10
kernel
Fix deferred
Red Hat Enterprise Linux 6
kernel
Not affected
Red Hat Enterprise Linux 7
kernel
Not affected
Red Hat Enterprise Linux 7
kernel-rt
Not affected
Red Hat Enterprise Linux 8
kernel
Not affected
Red Hat Enterprise Linux 8
kernel-rt
Not affected
Red Hat Enterprise Linux 9
kernel
Fix deferred
Red Hat Enterprise Linux 9
kernel-rt
Fix deferred
| Product | Package | State | Advisory |
|---|---|---|---|
| Red Hat Enterprise Linux 10 | kernel | Fix deferred | n/a |
| Red Hat Enterprise Linux 6 | kernel | Not affected | n/a |
| Red Hat Enterprise Linux 7 | kernel | Not affected | n/a |
| Red Hat Enterprise Linux 7 | kernel-rt | Not affected | n/a |
| Red Hat Enterprise Linux 8 | kernel | Not affected | n/a |
| Red Hat Enterprise Linux 8 | kernel-rt | Not affected | n/a |
| Red Hat Enterprise Linux 9 | kernel | Fix deferred | n/a |
| Red Hat Enterprise Linux 9 | kernel-rt | Fix deferred | n/a |
No package ranges for this CVE.
Remediation
No remediation recorded yet.
References (14)
- https://access.redhat.com/security/cve/CVE-2026-72142 Vendor Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=2516414 Issue Tracking
- https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-58900 Advisory
- https://git.kernel.org/stable/c/016ef0f6ca4bc9bf0330ac41bd2ea349759643e3
- https://git.kernel.org/stable/c/0f29df3c3d607a9dbc14aed0e45504ced4d2e7ec
- https://git.kernel.org/stable/c/38d4947431b2410850409fda016b2ac9f640a4dd
- https://git.kernel.org/stable/c/60ed00d46616a9232e42ea7a3e3c0273d7cf7543
- https://git.kernel.org/stable/c/6d2c973926d0612360693bc559be2ffde836151b
- https://git.kernel.org/stable/c/c882e8cc68fb993700dc21fd6e754001e6297934
- https://git.kernel.org/stable/c/cb2fc37857693b55909fb77dc2c87cfbc1cdc476
- https://git.kernel.org/stable/c/e3e8b02d4773cfc5ad561d2e5505efde36c6927a
- https://lore.kernel.org/linux-cve-announce/2026081532-CVE-2026-72142-616e@gregkh/T
- https://nvd.nist.gov/vuln/detail/CVE-2026-72142
- https://www.cve.org/CVERecord?id=CVE-2026-72142
Change history (0)
No recorded changes yet.