Bug 2492757 (CVE-2026-53219) - CVE-2026-53219 kernel: netfilter: x_tables: avoid leaking percpu counter pointers
Summary: CVE-2026-53219 kernel: netfilter: x_tables: avoid leaking percpu counter poin...
Keywords:
Status: NEW
Alias: CVE-2026-53219
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-06-25 10:04 UTC by OSIDB Bzimport
Modified: 2026-06-25 23:28 UTC (History)
2 users (show)

Fixed In Version:
Clone Of:
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Last Closed:
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Description OSIDB Bzimport 2026-06-25 10:04:09 UTC
In the Linux kernel, the following vulnerability has been resolved:

netfilter: x_tables: avoid leaking percpu counter pointers

The native and compat get-entries paths copy the fixed rule entry header
from the kernelized rule blob to userspace before overwriting the entry's
counter fields with a sanitized counter snapshot.

On SMP kernels, entry->counters.pcnt contains the percpu allocation
address used by x_tables rule counters. A caller can provide a userspace
buffer that faults during the initial fixed-header copy after pcnt has
been copied but before the later sanitized counter copy runs. The syscall
then returns -EFAULT while leaving the raw percpu pointer in userspace.

Copy only the fixed entry prefix before counters from the kernelized rule
blob, then copy the sanitized counter snapshot into the counter field.
Apply this ordering to the IPv4, IPv6, and ARP native and compat
get-entries implementations so a fault cannot expose the internal percpu
counter pointer.


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