High severity · published Sep 11, 2026
CVE-2026-89503
ring-buffer: Fix subbuf resize race with ring_buffer_alloc_read_page()
7.8
CVSS
0.2%
EPSS
No
On KEV
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it can allocate a reader page with an outdated order.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.
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 6% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
LI
Linux · Linux
bce761d757452ba5eb77e11fecc37a04b67494e7 before 2313ff69bd237aad264a5913907f374f958335a2; bce761d757452ba5eb77e11fecc37a04b67494e7 before 2dc510957fe8fd098ab3c3147ebdf34d00cd2734; bce761d757452ba5eb77e11fecc37a04b67494e7 before 53106e9262a310ef2c9a9321168c03705940c678; bce761d757452ba5eb77e11fecc37a04b67494e7 before e743527c5bfdceda1095bc0a9e596e2aebb6a9c3; 6.8 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-89503
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-89503
git.kernel.org
https://git.kernel.org/stable/c/2313ff69bd237aad264a5913907f374f958335a2
git.kernel.org
https://git.kernel.org/stable/c/2dc510957fe8fd098ab3c3147ebdf34d00cd2734
git.kernel.org
https://git.kernel.org/stable/c/53106e9262a310ef2c9a9321168c03705940c678
git.kernel.org
https://git.kernel.org/stable/c/e743527c5bfdceda1095bc0a9e596e2aebb6a9c3
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