Race Condition Affecting kernel-libbpf-static package, versions <0:6.1.127-135.201.amzn2023


Severity

Recommended
high

Based on Amazon Linux security rating.

Threat Intelligence

EPSS
0.04% (14th percentile)

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  • Snyk IDSNYK-AMZN2023-KERNELLIBBPFSTATIC-8688815
  • published6 Feb 2025
  • disclosed20 Jan 2025

Introduced: 20 Jan 2025

CVE-2025-21655  (opens in a new tab)
CWE-362  (opens in a new tab)

How to fix?

Upgrade Amazon-Linux:2023 kernel-libbpf-static to version 0:6.1.127-135.201.amzn2023 or higher.
This issue was patched in ALAS2023-2025-823.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-libbpf-static package and not the kernel-libbpf-static package as distributed by Amazon-Linux. See How to fix? for Amazon-Linux:2023 relevant fixed versions and status.

In the Linux kernel, the following vulnerability has been resolved:

io_uring/eventfd: ensure io_eventfd_signal() defers another RCU period

io_eventfd_do_signal() is invoked from an RCU callback, but when dropping the reference to the io_ev_fd, it calls io_eventfd_free() directly if the refcount drops to zero. This isn't correct, as any potential freeing of the io_ev_fd should be deferred another RCU grace period.

Just call io_eventfd_put() rather than open-code the dec-and-test and free, which will correctly defer it another RCU grace period.

CVSS Base Scores

version 3.1