Kernel memory corruption via RCU hook-list race
Published Jul 19, 2026 · Updated Jul 19, 2026
Race condition in Linux Kernel nf_tables allows local users to read or corrupt kernel memory through concurrent Netlink requests. The deletion preparation path moves hooks out of an RCU-protected base-chain or flow-table list while Netlink dump readers can still traverse it, producing invalid hook pointers. CAP_NET_ADMIN is required but is obtainable inside user namespaces; a successful race supports memory disclosure or corruption, host crash or hang, and privilege escalation.
Summary
What happened
Race condition in Linux Kernel nf_tables allows local users to read or corrupt kernel memory through concurrent Netlink requests. The deletion preparation path moves hooks out of an RCU-protected base-chain or flow-table list while Netlink dump readers can still traverse it, producing invalid hook pointers. CAP_NET_ADMIN is required but is obtainable inside user namespaces; a successful race supports memory disclosure or corruption, host crash or hang, and privilege escalation.
The record
- CVE
- CVE-2026-63858
- Published
- Jul 19, 2026
- Updated
- Jul 19, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux Kernel
- Classifications
- T1068
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Jul 19, 2026CVE publishedPublication date reported by the CVE source.
- Jul 19, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=5.10.122 <5.11
- Affected versionversion=5.15.47 <5.16
- Affected versionversion=5.17.15 <5.18
- Affected versionversion=5.18.4 <5.19
- Affected versionversion=5.19
- Affected versionversion=62d91062058b42bf70b2c3446aec397bb0ce15ee
- Affected versionversion=7a248f9c74f9f62799718c12efd9e9e391d60b6f
- Affected versionversion=99180dec5ae582227219d1fdd0dd5ccf53ec7491
- Affected versionversion=b6d9014a3335194590abdd2a2471ef5147a67645 <10f79dbd7719d1da9f5884d13060322d8729f091
- Affected versionversion=b6d9014a3335194590abdd2a2471ef5147a67645 <4e69bfb32b2db323d9205fdb30e284481b37817c
- Affected versionversion=f275989ad04159dbfc62cefb65ba9c5ba1d7c34f
What conditions does exploitation require?
What is affected?
Published CVSS scores
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.
Weakness, pattern, technique
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
See the directory against your own environment.
Your stack
Check the software in your environment
Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.
Book a demo