What is CVE-2021-35977?

CVE-2021-35977 is a critical-severity vulnerability in Digi 6350-Sr, classified under Buffer Copy without Checking Size of Input (Classic Buffer Overflow). CVSS score: 9.8/10. Published 2021-10-08.

How severe is CVE-2021-35977?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Buffer overflow in Digi 6350-Sr

CVE-2021-35977

An issue was discovered in Digi RealPort for Windows through 4.8.488.0. A buffer overflow exists in the handling of ADDP discovery response messages. This could result in arbitrary code execution.

Vulnerability class: Buffer Overflow

Published 2021-10-08 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.016 (74.5th percentile), scored 2026-09-30.

Low probability of exploitation in the next 30 days, but still tracked. 75th percentile — 74.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.016 · newest: 0.016 · change: 0.000

Affected products

Weakness classification (CWE)

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

References

raw.githubusercontent.com/reidmefirst/vuln-disclosure/main/2021-02.txt (Third Party Advisory)

Frequently asked questions

What is CVE-2021-35977?: CVE-2021-35977 is a critical-severity vulnerability in Digi 6350-Sr, classified under Buffer Copy without Checking Size of Input (Classic Buffer Overflow). CVSS score: 9.8/10. Published 2021-10-08.
How severe is CVE-2021-35977?: Critical severity. CVSS v3 base score is 9.8 out of 10.