What is CVE-2020-36177?

CVE-2020-36177 is a critical-severity vulnerability in Wolfssl, classified under Out-of-bounds Write. CVSS score: 9.8/10. Published 2021-01-06.

How severe is CVE-2020-36177?

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

Buffer overflow in Wolfssl

CVE-2020-36177

RsaPad_PSS in wolfcrypt/src/rsa.c in wolfSSL before 4.6.0 has an out-of-bounds write for certain relationships between key size and digest size.

Vulnerability class: Buffer Overflow

Published 2021-01-06 · 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: 0.035 (88.8th percentile), scored 2026-09-30.

Low probability of exploitation in the next 30 days, but still tracked. 89th percentile — 88.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.035 · newest: 0.035 · change: 0.000

Affected products

Wolfssl

Weakness classification (CWE)

CWE-787 — Out-of-bounds Write

References

github.com/wolfSSL/wolfssl/commit/63bf5dc56ccbfc12a73b06327361687091a4c6f7 (Patch, Third Party Advisory)
github.com/wolfSSL/wolfssl/pull/3426 (Patch, Third Party Advisory)
github.com/wolfSSL/wolfssl/commit/fb2288c46dd4c864b78f00a47a364b96a09a5c0f (Patch, Third Party Advisory)
bugs.chromium.org/p/oss-fuzz/issues/detail (Exploit, Mailing List, Third Party Advisory)
github.com/wolfSSL/wolfssl/releases/tag/v4.6.0-stable (Third Party Advisory)

Frequently asked questions

What is CVE-2020-36177?: CVE-2020-36177 is a critical-severity vulnerability in Wolfssl, classified under Out-of-bounds Write. CVSS score: 9.8/10. Published 2021-01-06.
How severe is CVE-2020-36177?: Critical severity. CVSS v3 base score is 9.8 out of 10.