i2c: imx: fix locked bus on SMBus block-read of 0 (atomic)
Key facts
- Attack vector
- —
- Privileges required
- —
- User interaction
- —
- Attack complexity
- —
- Impact type
- —
- Confidentiality · integrity · availability
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- Fix status
- Partial Red Hat: 2 without a fix
No CVSS vector from any source. Fix status from CNA and Red Hat.
Summary
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
- Fix · CNA Linux (Linux) Fixed in 5.10.266, 5.15.217, 6.1.184, 6.6.148, 6.12.101, 6.18.40, 7.1.5, 7.2
Vendor assessments
Red Hat
Red Hat rating: Low. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
Not affected: 3 products
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
Timeline
- 2026-10-02 Threatist record created from CVE-2026-72142
- 2026-10-03 Alias added: GHSA-63x6-874m-qjjg
- 2026-11-06 CISA SSVC decision points changed
References
Other 8
- https://git.kernel.org/stable/c/0f29df3c3d607a9dbc14aed0e45504ced4d2e7ec
- https://git.kernel.org/stable/c/38d4947431b2410850409fda016b2ac9f640a4dd
- https://git.kernel.org/stable/c/e3e8b02d4773cfc5ad561d2e5505efde36c6927a
- https://git.kernel.org/stable/c/016ef0f6ca4bc9bf0330ac41bd2ea349759643e3
- https://git.kernel.org/stable/c/c882e8cc68fb993700dc21fd6e754001e6297934
- https://git.kernel.org/stable/c/6d2c973926d0612360693bc559be2ffde836151b
- https://git.kernel.org/stable/c/60ed00d46616a9232e42ea7a3e3c0273d7cf7543
- https://git.kernel.org/stable/c/cb2fc37857693b55909fb77dc2c87cfbc1cdc476
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Sources
- CVE-2026-72142 · CVE Program
- CVE-2026-72142 · NVD
- FIRST EPSS
- GHSA-63x6-874m-qjjg · GitHub Advisory Database · CC BY 4.0
- CVE-2026-72142 · Red Hat security data · CC BY 4.0
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