CVE Catalog

CVE-2026-89748

HighCVSS 7.8
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.15%

5th percentile - higher than 5% of all known CVEs

Summary

In the Linux kernel, simple_ring_buffer_swap_reader_page() starts with retry set to 8 and decrements it only after a failed link replacement. On the final attempt, a successful replacement leaves retry at zero while a failed one leaves it at -1, so the !retry test reverses both outcomes and can corrupt the ring buffer.

Risk Assessment

The faulty retry logic can lead to ring buffer corruption and unpredictable behavior in the tracing mechanism. This may result in loss of diagnostic data or a kernel crash.

Recommendation

Update the Linux kernel to a version with the fix that treats only a negative counter as exhaustion and returns the documented -EBUSY error. After updating, test the reader page swap mechanism in a test environment.

Other vulnerabilities in Linux kernel

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Original NVD description (English source)

In the Linux kernel, the following vulnerability has been resolved: tracing: Fix retry exhaustion in simple ring buffer reader swap simple_ring_buffer_swap_reader_page() starts with retry set to 8 and post-decrements it only after a failed link replacement. On the final attempt, a successful replacement leaves retry at zero, while a failed replacement leaves it at -1. The current !retry test reverses both outcomes. It returns an error after a successful final replacement, leaving the link update complete but the reader bookkeeping unfinished. After a failed final replacement, it falls through and updates the head and reader pointers as though the replacement succeeded, which can corrupt the ring. Treat only a negative counter as exhaustion and return the documented -EBUSY error.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS