# CVE-2026-89748

## Summary

- **CVE ID:** CVE-2026-89748
- **Severity:** HIGH
- **CVSS Score:** 7.8 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H)
- **CWE:** N/A
- **Published:** Sep 11, 2026
- **Last Modified:** Sep 13, 2026

## Description

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.

## Affected Products

- Linux — Linux (34e5b958bdad0f9cf16306368bbc2dc5b2a50143)
- Linux — Linux (7.1)
- Linux — Linux (0)
- Linux — Linux (7.2.4)
- Linux — Linux (7.3-rc1)

## References

- [CNA](https://git.kernel.org/stable/c/df02489aa3aa1834659f0d20c89f7d212047d268)
- [CNA](https://git.kernel.org/stable/c/e0d3aed7b12cf37b74c7cc5265073d0263b49cde)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.15%
- **EPSS Percentile:** 4.9

---
_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-18._