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CVE-2021-23133

18
FAUCET Score

CVE-2021-23133 is a race condition vulnerability in the Linux kernel's SCTP socket implementation (net/sctp/socket.c) affecting versions before 5.12-rc8, including distributions like Debian and Fedora. This flaw allows an attacker with network service privileges or an unprivileged user (under specific BPF configurations) to achieve kernel privilege escalation. The vulnerability has a CVSS score of 7.0 (HIGH), indicating a local attack vector with high complexity, but leading to full confidentiality, integrity, and availability compromise. There is currently no known active exploitation, public exploit code (Metasploit, Nuclei, ExploitDB), or significant community discussion surrounding this CVE.

Impacted Technologies

VendorProductVersion(s)CPE
< 5.12-rc8CPE match
cpe:2.3:a:linux:linux_kernel:*:*:*:*:*:*:*:*
>= 4.10, < 4.14.232CPE matchmatch criteria
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
>= 4.15, < 4.19.189CPE matchmatch criteria
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
>= 4.20, < 5.4.114CPE matchmatch criteria
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
>= 5.5, < 5.10.32CPE matchmatch criteria
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

6.7MEDIUM

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

Attack Vector
LOCAL
Attack Complexity
LOW
Privileges Required
HIGH
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
0.8
Impact Score
5.9
CvssVersion
3.1

Exploit Intelligence

EPSS Score
0.48%
Probability of exploitation in next 30 days
EPSS Percentile
38.8%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0048 is in the 79th percentile among its peer group of 1,525 CVEs.

Social Chatter

No social media mentions found for this CVE.

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.2 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.4 InfoSec Media, 0.1 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (13)

microsoftpatch availablevia msrc
Product: CBL Mariner 1.0 x64Fixed in: 5.10.60.1-1
microsoftpatch availablevia msrc
Product: 16919-16820Fixed in: -
microsoftpatch availablevia msrc
Product: 16920-16823Fixed in: 5.10.78.1-1
microsoftpatch availablevia msrc
Product: cbl2 kernel 5.10.78.1-1 on CBL Mariner 2.0Fixed in: 5.10.78.1-1
microsoftpatch availablevia msrc
Product: CBL Mariner 1.0 ARMFixed in: 5.10.60.1-1
microsoftpatch availablevia msrc
Product: CBL Mariner 2.0 ARMFixed in: 5.10.78.1-1
microsoftpatch availablevia msrc
Product: CBL Mariner 2.0 x64Fixed in: 5.10.78.1-1
microsoftpatch availablevia msrc
Product: cm1 kernel 5.10.60.1-1 on CBL Mariner 1.0Fixed in: -
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8Fixed in: kernel-rt-0:4.18.0-348.rt7.130.el8
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8Fixed in: kernel-0:4.18.0-348.el8
View patch
debianworkaround availablevia nvd_reference
View patch
redhatend of lifevia redhat_api
Product: Red Hat Enterprise Linux 7Fixed in: kernel-rt
redhatend of lifevia redhat_api
Product: Red Hat Enterprise Linux 7Fixed in: kernel

Vendor Advisories (3)

microsoft2023-Mar/CVE-2021-23133

CVE-2021-23133

Mar 14, 2023
redhatCVE-2021-23133Moderate

kernel: Race condition in sctp_destroy_sock list_del

Apr 18, 2021
microsoft2021-Apr/CVE-2021-23133Important

Linux Kernel sctp_destroy_sock race condition

Apr 13, 2021

References

git.kernel.org / pub/scm/linux/kernel/git/torvalds/linux.git/commit
Mailing ListPatchVendor Advisory
lists.debian.org / debian-lts-announce/2021/06/msg00019.html
MitigationThird Party Advisory
lists.debian.org / debian-lts-announce/2021/06/msg00020.html
MitigationThird Party Advisory
lists.fedoraproject.org / archives/list/package-announce%40lists.fedoraproject.org/message/CUX2CA63453G34C6KYVBLJXJXEARZI2X
lists.fedoraproject.org / archives/list/package-announce%40lists.fedoraproject.org/message/PAEQ3H6HKNO6KUCGRZVYSFSAGEUX23JL
lists.fedoraproject.org / archives/list/package-announce%40lists.fedoraproject.org/message/XZASHZVCOFJ4VU2I3BN5W5EPHWJQ7QWX
security.netapp.com / advisory/ntap-20210611-0008
Third Party Advisory
openwall.com / lists/oss-security/2021/04/18/2
ExploitMailing ListPatchThird Party Advisory
openwall.com / lists/oss-security/2021/05/10/1
Mailing ListPatchThird Party Advisory
openwall.com / lists/oss-security/2021/05/10/2
Mailing ListPatchThird Party Advisory
openwall.com / lists/oss-security/2021/05/10/3
Mailing ListPatchThird Party Advisory
openwall.com / lists/oss-security/2021/05/10/4
Mailing ListPatchThird Party Advisory