Privilege escalation via stale packet-ring ownership state
Published Jan 26, 2022 · Updated Oct 21, 2025
Double free in packet_set_ring() in Linux Kernel before 5.4.168, 5.10.88, 5.15.11, or 5.16-rc6 allows local users to gain privileges. When a packet socket switches ring versions, shared union fields can retain stale tpacket_v3 rx_owner_map state; the error path frees that bitmap even though no pg_vec-backed ring allocated it. A low-privileged local user must issue crafted packet-socket syscalls; resulting kernel-memory corruption enables privilege escalation or a system crash.
Summary
What happened
Double free in packet_set_ring() in Linux Kernel before 5.4.168, 5.10.88, 5.15.11, or 5.16-rc6 allows local users to gain privileges. When a packet socket switches ring versions, shared union fields can retain stale tpacket_v3 rx_owner_map state; the error path frees that bitmap even though no pg_vec-backed ring allocated it. A low-privileged local user must issue crafted packet-socket syscalls; resulting kernel-memory corruption enables privilege escalation or a system crash.
The record
- CVE
- CVE-2021-22600
- Published
- Jan 26, 2022
- Updated
- Oct 21, 2025
- Vendor
- The Linux Kernel Organization
- Product
- Linux Kernel
- Classifications
- CWE-415, T1068
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Jan 26, 2022CVE publishedPublication date reported by the CVE source.
- Oct 21, 2025Record 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.
- Affected versionversion=unspecified <5.10.88
- Affected versionversion=unspecified <5.15.11
- Affected versionversion=unspecified <5.16-rc6
- Affected versionversion=unspecified <5.4.168
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.
Public exploit references
No public exploit references are available in this record.
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Reported exploitation
- CISA Known Exploited Vulnerabilities catalog listingknown exploited catalog
Technologies
Your stack
See the directory against your own environment.
Your stack
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