CVE-2021-38199 [Medium] | Denial of Service in Linux Kernel

CVE-2021-38199 is rated Moderate Risk (49.4/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 1.20%). EPSS rose +1.01% over the last day, indicating growing attacker interest. Review affected assets and schedule remediation.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-06-15	0.19%	1.20%	+1.01%
2	2026-04-21	0.31%	0.19%	-0.12%
3	2025-12-11	—	0.31%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-06-15

0.19%

1.20%

+1.01%

2026-04-21

0.31%

0.19%

-0.12%

2025-12-11

—

0.31%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
6.5	3.1	MEDIUM	`CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H` Click to expand Attack vector (AV:A) Attacker has to be nearby on the network—same office, same link, that vibe—not the whole wide internet. Attack complexity (AC:L) Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup. Privileges required (PR:N) No account or special rights needed—anonymous or random user is enough. User interaction (UI:N) Nobody has to click “OK” or open a trap file; it can work without a victim helping. Scope (S:U) Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems. Confidentiality (C:N) Doesn’t really leak secrets in a meaningful way. Integrity (I:N) Data isn’t meaningfully altered or forged. Availability (A:H) Could take the service down hard or make it unusable for people who depend on it.	2.8	3.6	[email protected]
3.3	2.0	LOW	`AV:A/AC:L/Au:N/C:N/I:N/A:P` Click to expand Access vector (AV:A) Requires access to an adjacent network segment. Access complexity (AC:L) Exploitation conditions are straightforward and predictable. Authentication (AU:N) No authentication is required. Confidentiality impact (C:N) No confidentiality impact. Integrity impact (I:N) No integrity impact. Availability impact (A:P) Partial availability impact.	6.5	2.9	[email protected]

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

6.5

3.1

MEDIUM

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

Attack vector (AV:A): Attacker has to be nearby on the network—same office, same link, that vibe—not the whole wide internet.
Attack complexity (AC:L): Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N): No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N): Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U): Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N): Doesn’t really leak secrets in a meaningful way.
Integrity (I:N): Data isn’t meaningfully altered or forged.
Availability (A:H): Could take the service down hard or make it unusable for people who depend on it.

2.8

3.6

[email protected]

3.3

2.0

LOW

AV:A/AC:L/Au:N/C:N/I:N/A:P Click to expand

Access vector (AV:A): Requires access to an adjacent network segment.
Access complexity (AC:L): Exploitation conditions are straightforward and predictable.
Authentication (AU:N): No authentication is required.
Confidentiality impact (C:N): No confidentiality impact.
Integrity impact (I:N): No integrity impact.
Availability impact (A:P): Partial availability impact.

6.5

2.9

[email protected]

OS Trackers for CVE-2021-38199

vendor	priority	summary	link
`debian`	not yet assigned	CVE-2021-38199 not yet assigned priority: Debian including 1 source packages (linux), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5.	https://security-tracker.debian.org/tracker/CVE-2021-38199
`redhat`	low	—	https://access.redhat.com/security/cve/CVE-2021-38199
`suse`	medium	CVE-2021-38199 severity moderate: SUSE including 14 source package names (kernel-default, kernel-default-base, …), 180 product×package rows across 47 product lines (HPE Helion OpenStack 8, SUSE CaaS Platform 4.0, … (47 product lines)): Known Not Affected 180.	https://www.suse.com/security/cve/CVE-2021-38199/
`ubuntu`	medium	CVE-2021-38199 medium priority: Ubuntu including 168 source packages (linux, linux-allwinner, …), 2116 status rows across 15 suites (bionic, focal, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): DNE 1640, not-affected 217, released 212, ignored 47.	https://ubuntu.com/security/CVE-2021-38199

Affected software / configurations for CVE-2021-38199

Vendor	Product	Version	Raw CPE
linux	linux_kernel	< 5.13.4	cpe:2.3:o:linux:linux_kernel::::::::
netapp	hci_bootstrap_os	—	cpe:2.3:o:netapp:hci_bootstrap_os:-:::::::*
netapp	hci_management_node	—	cpe:2.3:a:netapp:hci_management_node:-:::::::*
netapp	solidfire	—	cpe:2.3:a:netapp:solidfire:-:::::::*
netapp	element_software	—	cpe:2.3:a:netapp:element_software:-:::::::*
debian	debian_linux	9.0	cpe:2.3:o:debian:debian_linux:9.0:::::::*
debian	debian_linux	11.0	cpe:2.3:o:debian:debian_linux:11.0:::::::*

References for CVE-2021-38199

URL	Tags
https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.13.4	Mailing List Patch Vendor Advisory
https://github.com/torvalds/linux/commit/dd99e9f98fbf423ff6d365b37a98e8879170f17c	Patch Third Party Advisory
https://lists.debian.org/debian-lts-announce/2021/10/msg00010.html	Mailing List Third Party Advisory
https://lists.debian.org/debian-lts-announce/2021/12/msg00012.html	Mailing List Third Party Advisory
https://security.netapp.com/advisory/ntap-20210902-0010/	Third Party Advisory
https://www.debian.org/security/2021/dsa-4978	Third Party Advisory

URL

CVE-2021-38199

Exploit prediction scoring system (EPSS) score for CVE-2021-38199

Common vulnerability scoring system (CVSS) metrics for CVE-2021-38199

Weakness enumeration for CVE-2021-38199

OS Trackers for CVE-2021-38199

Affected software / configurations for CVE-2021-38199

References for CVE-2021-38199