Memory exhaustion via stale nexthop listener state
Published May 21, 2024 · Updated May 11, 2026
Memory leakage in Linux kernel 5.11 through 5.14.8 allows local users to consume kernel memory through nexthop listener teardown. When unregister_nexthop_notifier() removes a listener, the notification chain fails to replay delete events for nexthops whose devices survive a devlink reload, leaving mlxsw nexthop objects referenced and unfreed. Triggering the demonstrated path requires low-privilege local access plus control of nexthop and device reload operations; repeated teardown consumes memory and can interrupt service.
Summary
What happened
Memory leakage in Linux kernel 5.11 through 5.14.8 allows local users to consume kernel memory through nexthop listener teardown. When unregister_nexthop_notifier() removes a listener, the notification chain fails to replay delete events for nexthops whose devices survive a devlink reload, leaving mlxsw nexthop objects referenced and unfreed. Triggering the demonstrated path requires low-privilege local access plus control of nexthop and device reload operations; repeated teardown consumes memory and can interrupt service.
The record
- CVE
- CVE-2021-47371
- Published
- May 21, 2024
- Updated
- May 11, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- CWE-400, T1499
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- May 21, 2024CVE publishedPublication date reported by the CVE source.
- May 11, 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?
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- Affected versionversion=2a014b200bbd973cc96e082a5bc445fe20b50f32 <3106a0847525befe3e22fc723909d1b21eb0d520
- Affected versionversion=2a014b200bbd973cc96e082a5bc445fe20b50f32 <741760fa6252628a3d3afad439b72437d4b123d9
- Affected versionversion=5.11
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
What attackers are doing with it
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Public exploit references
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Technologies
Your stack
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Your stack
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