What is CVE-2020-12140?

CVE-2020-12140 is a high-severity vulnerability in Contiki-Ng, classified under Buffer Copy without Checking Size of Input (Classic Buffer Overflow). CVSS score: 8.8/10. Published 2021-12-07.

How severe is CVE-2020-12140?

High severity. CVSS v3 base score is 8.8 out of 10.

Is CVE-2020-12140 known to be exploited?

1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Buffer overflow in Contiki-Ng

CVE-2020-12140

A buffer overflow in os/net/mac/ble/ble-l2cap.c in the BLE stack in Contiki-NG 4.4 and earlier allows an attacker to execute arbitrary code via malicious L2CAP frames.

Vulnerability class: Buffer Overflow

Published 2021-12-07 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.009 (58.7th percentile), scored 2026-09-30.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 59th percentile — 58.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.009 · newest: 0.009 · change: 0.000

Affected products

Contiki-Ng

Weakness classification (CWE)

CWE-120 — Buffer Copy without Checking Size of Input (Classic Buffer Overflow)

Public proof-of-concept exploits

fuzzware-fuzzer/hoedur-experiments

References

twitter.com/ScepticCtf (Third Party Advisory)
github.com/contiki-ng/contiki-ng/pull/1662 (Patch, Third Party Advisory)

Frequently asked questions

What is CVE-2020-12140?: CVE-2020-12140 is a high-severity vulnerability in Contiki-Ng, classified under Buffer Copy without Checking Size of Input (Classic Buffer Overflow). CVSS score: 8.8/10. Published 2021-12-07.
How severe is CVE-2020-12140?: High severity. CVSS v3 base score is 8.8 out of 10.
Is CVE-2020-12140 known to be exploited?: 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.