CVE-2026-64572

Kernel use-after-free via premature fib_alias free

Published Aug 5, 2026 · Updated Aug 5, 2026

Use-after-free in the Linux IPv4 FIB allows local users with CAP_NET_ADMIN to trigger a freed-memory read during failed route insertion. On notifier rejection, fib_table_insert removes new_fa with hlist_del_rcu but immediately calls kmem_cache_free instead of deferring reclamation for RCU readers. A concurrent fib_table_lookup then reads the freed 56-byte fib_alias; the demonstrated result is a KASAN fault, not established code execution.

CVSS severityUnavailable
Unscored
EPSS probability0.20%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in the Linux IPv4 FIB allows local users with CAP_NET_ADMIN to trigger a freed-memory read during failed route insertion. On notifier rejection, fib_table_insert removes new_fa with hlist_del_rcu but immediately calls kmem_cache_free instead of deferring reclamation for RCU readers. A concurrent fib_table_lookup then reads the freed 56-byte fib_alias; the demonstrated result is a KASAN fault, not established code execution.

The record

CVE
CVE-2026-64572
Published
Aug 5, 2026
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
Unavailable
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Aug 5, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=5.6
  2. Affected versionversion=a6c76c17df021b141b0d306828c9fe4ba2d2717c <8150b5365f026e72250cacc527ea00be30f40105
  3. Affected versionversion=a6c76c17df021b141b0d306828c9fe4ba2d2717c <b8d2ea75c76abcd0d72679c2f488271f573e32fb
  4. Affected versionversion=a6c76c17df021b141b0d306828c9fe4ba2d2717c <cb8be318b4432abd88d3172ec157330f27a5f7a7
  5. Affected versionversion=a6c76c17df021b141b0d306828c9fe4ba2d2717c <d007056868723de9c0cc3f5ffaad47a8d468b9a4
  6. Affected versionversion=a6c76c17df021b141b0d306828c9fe4ba2d2717c <f2f152e94a67bc746afaf05a1b2702c195553112

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

The Linux Kernel Organization · Linuxversion=5.6; version=a6c76c17df021b141b0d306828c9fe4ba2d2717c <8150b5365f026e72250cacc527ea00be30f40105; version=a6c76c17df021b141b0d306828c9fe4ba2d2717c <b8d2ea75c76abcd0d72679c2f488271f573e32fb; version=a6c76c17df021b141b0d306828c9fe4ba2d2717c <cb8be318b4432abd88d3172ec157330f27a5f7a7; version=a6c76c17df021b141b0d306828c9fe4ba2d2717c <d007056868723de9c0cc3f5ffaad47a8d468b9a4; version=a6c76c17df021b141b0d306828c9fe4ba2d2717c <f2f152e94a67bc746afaf05a1b2702c195553112

Published CVSS scores

No CVSS assessment is available in this record.

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

No sourced classifications are available.

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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