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Weekly Signal
Live intelligence Updated 20 Aug 2026 · 23:28 UTC

Broadcom, Debian, Fedoraproject +2 more · Brocade Fabric Operating System, Debian Linux, Fedora +12 more

CVE-2021-23133

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 net...

Recommended action

Handle this through the normal risk-based patching cycle while monitoring for change. Debian Mitigation guidance Msg00019

View response plan
CVSS7.0
EPSS0.5%
KEVNo
ExploitationNone
RemediationExplicit patch identified ↓

Assessment

Why it matters

EPSS is 0.5%; technical severity is CVSS 7.0.

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.

Who should care

  • Teams operating Brocade Fabric Operating System, Debian Linux, Fedora +12 more
  • Vulnerability and exposure management teams
  • Security operations teams monitoring exploitation activity

Response plan

What I would do

  1. Confirm whether Brocade Fabric Operating System, Debian Linux, Fedora +12 more is present in the environment.
  2. Identify affected versions and establish whether vulnerable services are exposed or reachable.
  3. Debian Mitigation guidance Msg00019
  4. Review relevant security telemetry for evidence of attempted or successful exploitation.
  5. Document the remediation decision and track it to verified completion.

Treatment intelligence

Remediation intelligence

Not yet verified

Vendor sources are listed before government and third-party guidance. Confirm product applicability and change prerequisites before deployment.

Verification noteAutomated link verification has not completed for this guidance yet.

Patch

Mitigation

Technical details

CVSS vector
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
CWE
CWE-362
Affected versions
Broadcom Brocade Fabric Operating System (Version -); Debian Debian Linux (Version 9.0); Fedoraproject Fedora (Version 32 | Version 33 | Version 34); Linux Linux Kernel (End Excluding 4.4.269 | Start Including 4.5, End Excluding 4.9.269 | Start Including 4.10, End Excluding 4.14.233 | Start Including 4.15, End Excluding 4.19.191); Netapp Cloud Backup (Version -); Netapp H300e Firmware (Version -); Netapp H300s Firmware (Version -); Netapp H410c Firmware (Version -)
Fixed versions
Linux Linux Kernel (Fixed from 4.4.269, 4.9.269, 4.14.233, 4.19.191, 5.4.119, 5.10.37, 5.11.21, 5.12.4)
Published
22 April 2021
Attack vector
Local
Privileges required
Low
User interaction
None

Signal timeline

  1. CVE published
  2. Latest EPSS score: 0.5%
  3. Signal calculated at 11

External references

Live public intelligence This assessment combines public-source evidence. Validate the affected product, version and exposure against your own environment before making a risk decision.