VulnerabilityPublished 25 Jun 2026Updated 6 Nov 2026

CVE-2026-53219: Linux kernel · netfilter: x_tables: avoid leaking percpu counter pointers

Affects Linux kernelSource CVE Database V5

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Not known to be exploited · fixed in fb0521aff1e10e300d89725cc439d3ea74c828c5 : update Linux kernel when convenient.

Data as of 6 Nov 2026, 16:49 UTC

Severity

Unrated

Rated by Threat Radar · No CVSS score from NVD or the CNA

Thin evidence

One scorer or none

Exploitation: No evidence of active exploitation and no public proof of concept
Automatable: Attackers cannot reliably automate steps 1–4 of the kill chain
Technical impact: Limited control over the software or limited information exposure

CISA SSVC assessment, 2026-11-06.

Patch

Available – fixed in fb0521aff1e10e300d89725cc439d3ea74c828c5, f7f2fbb0e893a0238dc464f8d8c0f5609bec584f, b74ba3343eb44b2cbf7e9665918c287df1d52ebb +5

Exploitation evidence

Disclosed: evidence found.
CVE published 25 Jun 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 6 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 71ae0dff02d756e4d2ca710b79f2ff5390029a5f, < fb0521aff1e10e300d89725cc439d3ea74c828c5	Fixed in fb0521aff1e10e300d89725cc439d3ea74c828c5
LinuxLinux	Affected ≥ 71ae0dff02d756e4d2ca710b79f2ff5390029a5f, < f7f2fbb0e893a0238dc464f8d8c0f5609bec584f	Fixed in f7f2fbb0e893a0238dc464f8d8c0f5609bec584f
LinuxLinux	Affected ≥ 71ae0dff02d756e4d2ca710b79f2ff5390029a5f, < b74ba3343eb44b2cbf7e9665918c287df1d52ebb	Fixed in b74ba3343eb44b2cbf7e9665918c287df1d52ebb
LinuxLinux	Affected ≥ 71ae0dff02d756e4d2ca710b79f2ff5390029a5f, < b28e2fcad3db7e8687b15bc20bced26b5b7c920e	Fixed in b28e2fcad3db7e8687b15bc20bced26b5b7c920e
LinuxLinux	Affected ≥ 71ae0dff02d756e4d2ca710b79f2ff5390029a5f, < a0d16941adf3a501956d74aefd8d6e217906e79c	Fixed in a0d16941adf3a501956d74aefd8d6e217906e79c
LinuxLinux	Affected ≥ 71ae0dff02d756e4d2ca710b79f2ff5390029a5f, < 8d67e42ad3b1a95a152541015a07110e06992d6c	Fixed in 8d67e42ad3b1a95a152541015a07110e06992d6c

Description

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.

References

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