HOMEVULNERABILITIESCVE-2021-3640
HIGH

CVE-2021-3640

CWE-362Published: March 3, 2022· Updated: Jun 17, 2026

7.0
CVSS v3.1

Official Description

A flaw use-after-free in function sco_sock_sendmsg() of the Linux kernel HCI subsystem was found in the way user calls ioct UFFDIO_REGISTER or other way triggers race condition of the call sco_conn_del() together with the call sco_sock_sendmsg() with the expected controllable faulting memory page. A privileged local user could use this flaw to crash the system or escalate their privileges on the system.

NVD Source

Technical Analysis

CVE-2021-3640 requires local access, meaning attackers must already have a foothold on the target system.

Exploitation requires low privileges, which limits the exposure to scenarios where an attacker has already gained initial access.

A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), availability disruption (denial of service), with a CVSS base score of 7.0.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorLocal
Attack ComplexityHigh
Privileges Req.Low
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected Vendors & Products

Canonical1 product(s)
ubuntu linux
Debian1 product(s)
debian linux
Fedora1 product(s)
fedora
Linux1 product(s)
linux kernel
netapp16 product(s)
h300s firmwareh300sh700s firmwareh700sh300e firmwareh300eh500e firmwareh500eh700e firmwareh700eh410s firmwareh410s+4
Source: NVD CPE · 24 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

PATCHhttps://bugzilla.redhat.com/show_bug.cgi?id=1980646
PATCHhttps://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/net/bluetooth/sco.c?h=v5.16&id=99c23da0eed4fd20cae8243f2b51e10e66aa0951
PATCHhttps://github.com/torvalds/linux/commit/99c23da0eed4fd20cae8243f2b51e10e66aa0951
PATCHhttps://ubuntu.com/security/CVE-2021-3640
PATCHhttps://bugzilla.redhat.com/show_bug.cgi?id=1980646
PATCHhttps://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/net/bluetooth/sco.c?h=v5.16&id=99c23da0eed4fd20cae8243f2b51e10e66aa0951
PATCHhttps://github.com/torvalds/linux/commit/99c23da0eed4fd20cae8243f2b51e10e66aa0951
PATCHhttps://ubuntu.com/security/CVE-2021-3640
ADVISORYhttps://lists.debian.org/debian-lts-announce/2022/03/msg00011.html
ADVISORYhttps://lists.debian.org/debian-lts-announce/2022/03/msg00012.html
ADVISORYhttps://security.netapp.com/advisory/ntap-20220419-0003/
ADVISORYhttps://www.debian.org/security/2022/dsa-5096
ADVISORYhttps://www.openwall.com/lists/oss-security/2021/07/22/1
ADVISORYhttps://lists.debian.org/debian-lts-announce/2022/03/msg00011.html
ADVISORYhttps://lists.debian.org/debian-lts-announce/2022/03/msg00012.html
ADVISORYhttps://security.netapp.com/advisory/ntap-20220419-0003/
ADVISORYhttps://www.debian.org/security/2022/dsa-5096
ADVISORYhttps://www.openwall.com/lists/oss-security/2021/07/22/1

All References (18)

→
https://bugzilla.redhat.com/show_bug.cgi?id=1980646Issue Tracking · Patch · Third Party Advisory
→
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/net/bluetooth/sco.c?h=v5.16&id=99c23da0eed4fd20cae8243f2b51e10e66aa0951Patch · Vendor Advisory
→
https://github.com/torvalds/linux/commit/99c23da0eed4fd20cae8243f2b51e10e66aa0951Patch · Third Party Advisory
→
https://lists.debian.org/debian-lts-announce/2022/03/msg00011.htmlMailing List · Third Party Advisory
→
https://lists.debian.org/debian-lts-announce/2022/03/msg00012.htmlMailing List · Third Party Advisory
→
https://security.netapp.com/advisory/ntap-20220419-0003/Third Party Advisory
→
https://ubuntu.com/security/CVE-2021-3640Patch · Third Party Advisory
→
https://www.debian.org/security/2022/dsa-5096Third Party Advisory
→
https://www.openwall.com/lists/oss-security/2021/07/22/1Exploit · Mailing List · Third Party Advisory
→
https://bugzilla.redhat.com/show_bug.cgi?id=1980646Issue Tracking · Patch · Third Party Advisory
→
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/net/bluetooth/sco.c?h=v5.16&id=99c23da0eed4fd20cae8243f2b51e10e66aa0951Patch · Vendor Advisory
→
https://github.com/torvalds/linux/commit/99c23da0eed4fd20cae8243f2b51e10e66aa0951Patch · Third Party Advisory
→
https://lists.debian.org/debian-lts-announce/2022/03/msg00011.htmlMailing List · Third Party Advisory
→
https://lists.debian.org/debian-lts-announce/2022/03/msg00012.htmlMailing List · Third Party Advisory
→
https://security.netapp.com/advisory/ntap-20220419-0003/Third Party Advisory

Quick Facts

CVE IDCVE-2021-3640
CVSS Score7.0 / 10
SeverityHIGH
WeaknessCWE-362
CISA KEVNo
Affected5 vendor(s)
PublishedMar 3, 2022

Related CVEs (CWE-362)

CVE-2008-6598
10.0
CVE-2015-8556
10.0
CVE-2014-0703
10.0
CVE-2025-66419
10.0
CVE-2010-1228
10.0
CVE-2020-1660
9.9

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2021-3640 in threat intel feeds
  • →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWatch. CVE data is provided under the NVD usage policy.
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