Medium [CVE-2026-53219] avoid leaking percpu counter pointers
This medium-severity Red Hat Linux advisory covers CVE-2026-53219 affecting Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7.
Aggregated and source-linked by VulniPulse. Data sources, validation and limitations.
VulniPulse record published Record updated
Summary
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. 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.
This vulnerability allows for information disclosure due to improper handling of percpu counter pointers during the copying of rule entry headers to userspace. A local attacker could exploit this by causing a fault in a userspace buffer, leading to the exposure of internal kernel memory addresses.
Red Hat severity: Moderate — CVSS 5.5 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H). Weakness: CWE-1098.
Is CVE-2026-53219 exploited?
No exploitation is reported in the sources VulniPulse tracks: CVE-2026-53219 is not in the CISA KEV catalog (checked ) and this advisory does not report exploitation. That is not proof the vulnerability cannot be exploited.
How do I fix CVE-2026-53219?
The advisory VulniPulse tracks names no fixed release. Follow Red Hat's guidance for workarounds and updates.
Confirm against the vendor advisory before you patch.
Affected versions
No affected-version range was extracted from the source record. The vendor advisory is authoritative. Check it before change work.
Official advisory · medium-confidence parse· fetched 15 days ago·verify at source
Fixed versions
No fixed release is recorded yet. That does not prove no patch exists. Confirm against the vendor advisory.
Official advisory · medium-confidence parse· fetched 15 days ago·verify at source
Mitigation
The source record does not include mitigation steps. That does not mean no fix exists. Read the vendor advisory below for the authoritative guidance.
Official advisory · medium-confidence parse· fetched 15 days ago·verify at source
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