What’s Vulnerable › Vulnerabilities

CVE-2021-47195: spi: fix use-after-free of the add_lock mutex

• Severity: medium (CVSS 5.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2024-04-10 · updated 2026-06-17
• Weakness: CWE-416

Description

In the Linux kernel, the following vulnerability has been resolved: spi: fix use-after-free of the add_lock mutex Commit 6098475d4cb4 ("spi: Fix deadlock when adding SPI controllers on SPI buses") introduced a per-controller mutex. But mutex_unlock() of said lock is called after the controller is already freed: spi_unregister_controller(ctlr) -> put_device(&ctlr->dev) -> spi_controller_release(dev) -> mutex_unlock(&ctrl->add_lock) Move the put_device() after the mutex_unlock().

Affected products

• Linux kernel: from 5.15.0 (excl.) before 5.15.5 — fixed in 5.15.5

How to fix

Upgrade to a fixed version: Linux kernel 5.15.5. Check the vendor advisory for mitigations.

References

• https://git.kernel.org/stable/c/11eab327a2a8bd36c38afbff920ae1bd45588dd4
• https://git.kernel.org/stable/c/37330f37f6666c7739a44b2b6b95b047ccdbed2d
• https://git.kernel.org/stable/c/54c2c96eafcfd242e52e932ab54ace4784efe1dd
• https://git.kernel.org/stable/c/6c53b45c71b4920b5e62f0ea8079a1da382b9434
• https://git.kernel.org/stable/c/37330f37f6666c7739a44b2b6b95b047ccdbed2d
• https://git.kernel.org/stable/c/6c53b45c71b4920b5e62f0ea8079a1da382b9434

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