CVE-2021-23133
Low
No strong exploitation signal.
CVSS base
6.7
MEDIUM
CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
EPSS — probability of exploitation (30 days)
0.5%
39.8th percentile
CISA KEV
Not listed
Weakness / dates
CWE-362
Published 2021-04-22 · modified 2026-07-30
CVSS breakdown
CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
| Attack Vector | L | Local |
| Attack Complexity | L | Low |
| Privileges Required | H | High |
| User Interaction | N | None |
| Scope | U | Unchanged |
| Confidentiality | H | High |
| Integrity | H | High |
| Availability | H | High |
Timeline
- 2021-04-22 — Published (NVD)
- 2026-07-30 — Last modified (NVD)
Description
A race condition in Linux kernel SCTP sockets (net/sctp/socket.c) before 5.12-rc8 can lead to kernel privilege escalation from the context of a network service or an unprivileged process. If sctp_destroy_sock is called without sock_net(sk)->sctp.addr_wq_lock then an element is removed from the auto_asconf_splist list without any proper locking. This can be exploited by an attacker with network service privileges to escalate to root or from the context of an unprivileged user directly if a BPF_CGROUP_INET_SOCK_CREATE is attached which denies creation of some SCTP socket.
Affected
References
- http://www.openwall.com/lists/oss-security/2021/05/10/1
- http://www.openwall.com/lists/oss-security/2021/05/10/2
- http://www.openwall.com/lists/oss-security/2021/05/10/3
- http://www.openwall.com/lists/oss-security/2021/05/10/4
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=b166a20b07382b8bc1dcee2a448715c9c2c81b5b
- https://lists.debian.org/debian-lts-announce/2021/06/msg00019.html
- https://lists.debian.org/debian-lts-announce/2021/06/msg00020.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/CUX2CA63453G34C6KYVBLJXJXEARZI2X/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/PAEQ3H6HKNO6KUCGRZVYSFSAGEUX23JL/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/XZASHZVCOFJ4VU2I3BN5W5EPHWJQ7QWX/
- https://security.netapp.com/advisory/ntap-20210611-0008/
- exploit https://www.openwall.com/lists/oss-security/2021/04/18/2
- http://www.openwall.com/lists/oss-security/2021/05/10/1
- http://www.openwall.com/lists/oss-security/2021/05/10/2
- http://www.openwall.com/lists/oss-security/2021/05/10/3
- http://www.openwall.com/lists/oss-security/2021/05/10/4
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=b166a20b07382b8bc1dcee2a448715c9c2c81b5b
- https://lists.debian.org/debian-lts-announce/2021/06/msg00019.html
- https://lists.debian.org/debian-lts-announce/2021/06/msg00020.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/CUX2CA63453G34C6KYVBLJXJXEARZI2X/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/PAEQ3H6HKNO6KUCGRZVYSFSAGEUX23JL/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/XZASHZVCOFJ4VU2I3BN5W5EPHWJQ7QWX/
- https://security.netapp.com/advisory/ntap-20210611-0008/
- exploit https://www.openwall.com/lists/oss-security/2021/04/18/2