CVE-2021-3434

L2CAP: Stack based buffer overflow in le_ecred_conn_req()

4.9 Medium

Stack based buffer overflow in le_ecred_conn_req(). Zephyr versions >= v2.5.0 Stack-based Buffer Overflow (CWE-121). For more information, see https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-8w87-6rfp-cfrm

Attack profile

How easy it is to exploit

Attack vector: Local
Complexity: High
Privileges needed: None
User interaction: None

What an attacker can affect

Confidentiality: Low
Integrity: Low
Availability: Low

Exploit likelihood

0.21%Down 0.7 points since Jun 29, 2022

What each source reports

CVE List Score used 4.9

L2CAP: Stack based buffer overflow in le_ecred_conn_req()

Record: CVE-2021-3434
CVSS 3.1: 4.9 MediumCVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L
Weakness: CWE-121
Updated: 2026-11-02

EUVDEUVD-2021-26760 4.9

Record: EUVD-2021-26760
CVSS 3.1: 4.9 MediumCVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L
Updated: 2026-11-03

NVD 4.9

Record: CVE-2021-3434
CVSS 3.1: 4.9 MediumCVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L
CVSS 3.1: 7.8 HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CVSS 2.0: 4.6 MediumAV:L/AC:L/Au:N/C:P/I:P/A:P
Weakness: CWE-121, CWE-787
Updated: 2026-11-02

Affected products

History

History
Recorded	Changed	Sources
Nov 3, 2026	aliases, published	EUVD
Nov 2, 2026	first indexed	CVE List, NVD

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2021-3434 is a medium vulnerability (CVSS 4.9) in Zephyrproject Zephyr, published June 28, 2022. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.21%, the 11th percentile. No source names a fixed version.

References

github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-8w87-6rfp-cfrm