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CVE-2021-4454

18
FAUCET Score

CVE-2021-4454 is a Linux kernel vulnerability affecting the J1939 CAN bus protocol implementation. Specifically, an incorrect assumption about the session reference count in j1939_session_deactivate() could lead to a WARN_ON_ONCE trigger in concurrent scenarios. Rated 5.5 MEDIUM (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H), this local vulnerability could result in a denial of service. There is no evidence of active exploitation, public exploit code, or significant community discussion surrounding this CVE.

Impacted Technologies

VendorProductVersion(s)CPE
>= 5.4.138, < 5.4.232CPE matchmatch criteria
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
>= 5.10.56, < 5.10.168CPE matchmatch criteria
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
>= 5.13.8, < 5.14CPE matchmatch criteria
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
>= 5.14.1, < 5.15.93CPE matchmatch criteria
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
>= 5.16, < 6.1.11CPE matchmatch criteria
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

5.5MEDIUM

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

Attack Vector
LOCAL
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
Exploitability Score
1.8
Impact Score
3.6
CvssVersion
3.1

Exploit Intelligence

EPSS Score
0.23%
Probability of exploitation in next 30 days
EPSS Percentile
13.4%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0023 is in the 60th percentile among its peer group of 15,940 CVEs.

Social Chatter

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

Media Mentions

No media coverage found for this CVE.

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

Remediation

Vendor Patches (2)

redhatvendor investigatingvia redhat_api
Product: Red Hat Enterprise Linux 9Fixed in: kernel
redhatvendor investigatingvia redhat_api
Product: Red Hat Enterprise Linux 9Fixed in: kernel-rt

Vendor Advisories (1)

redhatCVE-2021-4454Low

kernel: can: j1939: fix errant WARN_ON_ONCE in j1939_session_deactivate

Mar 27, 2025

References

git.kernel.org / stable/c/1740a1e45eee65099a92fb502e1e67e63aad277d
Patch
git.kernel.org / stable/c/6950df42a03c9ac9290503ced3f371199cb68fa9
Patch
git.kernel.org / stable/c/9ab896775f98ff54b68512f345eed178bf961084
Patch
git.kernel.org / stable/c/b6d44072117bba057d50f7a2f96e5d070c65926d
Patch
git.kernel.org / stable/c/d0553680f94c49bbe0e39eb50d033ba563b4212d
Patch