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CVE-2021-3454

23
FAUCET Score

CVE-2021-3454 describes an Improper Handling of Length Parameter Inconsistency (CWE-130) and Reachable Assertion (CWE-617) vulnerability in Zephyr RTOS versions 2.4.0 and 2.5.0. A truncated L2CAP K-frame can cause an assertion failure, impacting the availability of affected systems. This vulnerability has a CVSS score of 7.5 (HIGH), indicating a network-based attack with low complexity, requiring no user interaction or privileges, and primarily impacting availability. While it is not currently listed on the KEV catalog or Hot List, its EPSS score is low, suggesting a low likelihood of exploitation. There is no public exploit code available for this vulnerability in Metasploit, Nuclei, or ExploitDB. Community discussion and media coverage are minimal, with only one article from BleepingComputer mentioning it.

Impacted Technologies

VendorProductVersion(s)CPE
>= 2.4.0, < 2.6.0CPE matchmatch criteria
cpe:2.3:o:zephyrproject:zephyr:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

4.3MEDIUM

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

Attack Vector
ADJACENT_NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
LOW
Exploitability Score
2.8
Impact Score
1.4
CvssVersion
3.1

Exploit Intelligence

EPSS Score
0.93%
Probability of exploitation in next 30 days
EPSS Percentile
57.0%
Percentile rank of EPSS score among Peer Group
As of 2026-07-28
Model: v2026.06.15
This CVE's current EPSS score of 0.0093 is in the 32nd percentile among its peer group of 51,553 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.4 GitHub mentions.

Media Mentions

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

Remediation

Patch Available

Vendor Patches (1)

github_advisorypatch availablevia nvd_reference
View patch

References

github.com / zephyrproject-rtos/zephyr/security/advisories/GHSA-fx88-6c29-vrp3
PatchThird Party Advisory