Buffer overflow in Wolfssl

CVE-2019-18840

In wolfSSL 4.1.0 through 4.2.0c, there are missing sanity checks of memory accesses in parsing ASN.1 certificate data while handshaking. Specifically, there is a one-byte heap-based buffer overflow inside the DecodedCert structure in GetName in wolfcrypt/src/asn.c because the domain name location index is mishandled. Because a pointer is overwritten, there is an invalid free.

Vulnerability class: Buffer Overflow

Published · last modified .

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.020 (79.6th percentile), scored .

Low probability of exploitation in the next 30 days, but still tracked. 80th percentile — 79.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2019-18840: held from 0.020 to 0.020.

EPSS over last 30 days · oldest: 0.020 · newest: 0.020 · change: 0.000

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2019-18840?
CVE-2019-18840 is a high-severity vulnerability in Wolfssl, classified under Out-of-bounds Write. CVSS score: 7.5/10. Published 2019-11-09.
How severe is CVE-2019-18840?
High severity. CVSS v3 base score is 7.5 out of 10.