CVE-2026-89503
Published Sep 11, 2026
Description
In the Linux kernel, the following vulnerability has been resolved: ring-buffer: Fix subbuf resize race with ring_buffer_alloc_read_page() ring_buffer_alloc_read_page() is racy with ring_buffer_subbuf_order_set, it can allocate a reader page with an outdated order. This isn't a big issue, the user can still re-allocate a new reader page and try again. However, what is more problematic is if the value of subbuf_order changes in the middle of ring_buffer_alloc_read_page(). In that case, bpage->order might not match the actual allocated memory. Use bpage->order for the allocation to prevent this race.
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References
Frequently Asked Questions
What is CVE-2026-89503? +
In the Linux kernel, the following vulnerability has been resolved:
ring-buffer: Fix subbuf resize race with ring_buffer_alloc_read_page()
ring_buffer_alloc_read_page() is racy with ring_buffer_subbuf_order_set,
it can allocate a reader page with an outdated order. This isn't a big
issue, the user can still re-allocate a new reader page and try again.
However, what is more problematic is if the value of subbuf_order
changes in the middle of ring_buffer_alloc_read_page(). In that case,
bpage->order might not match the actual allocated memory.
Use bpage->order for the allocation to prevent this race.
How do I check if I'm vulnerable to CVE-2026-89503? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.