Root privilege escalation via unlocked SCTP list removal
Published Apr 22, 2021 · Updated Sep 16, 2024
A race condition in Linux Kernel before 5.12-rc8 allows local users to gain root privileges through concurrent SCTP socket teardown. The sctp_destroy_sock function deletes auto_asconf_list from the per-network-namespace auto_asconf_splist without holding addr_wq_lock, allowing simultaneous socket creation to corrupt the list. The demonstrated path requires CAP_BPF and CAP_NET_ADMIN, while an unprivileged path also requires a preattached denying BPF program and enabled user namespaces; successful exploitation yields root access or a kernel crash.
Summary
What happened
A race condition in Linux Kernel before 5.12-rc8 allows local users to gain root privileges through concurrent SCTP socket teardown. The sctp_destroy_sock function deletes auto_asconf_list from the per-network-namespace auto_asconf_splist without holding addr_wq_lock, allowing simultaneous socket creation to corrupt the list. The demonstrated path requires CAP_BPF and CAP_NET_ADMIN, while an unprivileged path also requires a preattached denying BPF program and enabled user namespaces; successful exploitation yields root access or a kernel crash.
The record
- CVE
- CVE-2021-23133
- Published
- Apr 22, 2021
- Updated
- Sep 16, 2024
- Vendor
- The Linux Kernel Organization
- Product
- Linux Kernel
- Classifications
- CWE-362, T1068
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Apr 22, 2021CVE publishedPublication date reported by the CVE source.
- Sep 16, 2024Record 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 <5.12-rc8
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
- SCTP socket race proof of conceptproof of concept · demonstrated
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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