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Vulnerability record · CVE-2021-23133 · published 22 April 2021

CVE-2021-23133: Linux kernel race condition vulnerability

Linux · Linux Kernel

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.

7.0 CVSS 3.1 High EPSS 0.48% · top 60.9% CWE-362 · Race condition
7.0CVSS 3.1 base score, v2 6.9
0.48%EPSS exploitation probability, 30 days
NoNot in CISA KEV
15Affected product versions listed by NVD
24References, 2 tagged exploit
30 Jul 2026Last modified by 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.

CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected products

15 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
http://www.openwall.com/lists/oss-security/2021/05/10/1 Mailing ListPatchThird Party Advisory
http://www.openwall.com/lists/oss-security/2021/05/10/2 Mailing ListPatchThird Party Advisory
http://www.openwall.com/lists/oss-security/2021/05/10/3 Mailing ListPatchThird Party Advisory
http://www.openwall.com/lists/oss-security/2021/05/10/4 Mailing ListPatchThird Party Advisory
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=b166a20b07382b8bc1dcee2a448715c9c2c81b5b Mailing ListPatchVendor Advisory
https://lists.debian.org/debian-lts-announce/2021/06/msg00019.html MitigationThird Party Advisory
https://lists.debian.org/debian-lts-announce/2021/06/msg00020.html MitigationThird Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/CUX2CA63453G34C6KYVBLJX Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/PAEQ3H6HKNO6KUCGRZVYSFS Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/XZASHZVCOFJ4VU2I3BN5W5E Third Party Advisory
https://security.netapp.com/advisory/ntap-20210611-0008/ Third Party Advisory
https://www.openwall.com/lists/oss-security/2021/04/18/2 ExploitMailing ListPatchThird Party Advisory
http://www.openwall.com/lists/oss-security/2021/05/10/1 Mailing ListPatchThird Party Advisory
http://www.openwall.com/lists/oss-security/2021/05/10/2 Mailing ListPatchThird Party Advisory
http://www.openwall.com/lists/oss-security/2021/05/10/3 Mailing ListPatchThird Party Advisory
http://www.openwall.com/lists/oss-security/2021/05/10/4 Mailing ListPatchThird Party Advisory
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=b166a20b07382b8bc1dcee2a448715c9c2c81b5b Mailing ListPatchVendor Advisory
https://lists.debian.org/debian-lts-announce/2021/06/msg00019.html MitigationThird Party Advisory
https://lists.debian.org/debian-lts-announce/2021/06/msg00020.html MitigationThird Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/CUX2CA63453G34C6KYVBLJX Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/PAEQ3H6HKNO6KUCGRZVYSFS Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/XZASHZVCOFJ4VU2I3BN5W5E Third Party Advisory
https://security.netapp.com/advisory/ntap-20210611-0008/ Third Party Advisory
https://www.openwall.com/lists/oss-security/2021/04/18/2 ExploitMailing ListPatchThird Party Advisory

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Source: NIST National Vulnerability Database (record CVE-2021-23133), CISA KEV, FIRST EPSS (scores of 2026-10-10). This page is refreshed as NVD updates the record.