# CVE-2026-74733: gpio: pca953x: fix pca953x_irq_bus_sync_unlock regmap lock

CVE-2026-74733 is fixed in linux on 1 platform, first by DEBIAN-CVE-2026-74733, released September 4, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-74733
- Priority: High
- CVSS: 7.8 (Low)
- EPSS: 0.0013
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Aug 22, 2026
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-74733

## Description

In the Linux kernel, the following vulnerability has been resolved:  gpio: pca953x: fix pca953x_irq_bus_sync_unlock regmap lock  Locking is disabled in the regmap config as this driver uses its own lock. This means that all calls to regmap functions (read or write) must hold the i2c_lock. The function pca953x_irq_bus_sync_unlock() did not do this, and it was therefore possible that multiple threads could cause an incorrect register to be read/written.  A previous patch partly fixed this, but only protected the write to the interrupt mask register, and not the read from the direction register.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 13.5 (trixie) | 6.12.115-2 | [DEBIAN-CVE-2026-74733](https://patchblox.com/security/data/fix/linux/debian-cve-2026-74733.md) | Sep 4, 2026 |
| Linux | linux Debian 14 | 7.1.9-1 | [DEBIAN-CVE-2026-74733](https://patchblox.com/security/data/fix/linux/debian-cve-2026-74733.md) | Sep 4, 2026 |

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Data as of 2026-11-08T06:59:42Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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