Buffer overflow in Wolfssl

CVE-2019-11873

wolfSSL 4.0.0 has a Buffer Overflow in DoPreSharedKeys in tls13.c when a current identity size is greater than a client identity size. An attacker sends a crafted hello client packet over the network to a TLSv1.3 wolfSSL server. The length fields of the packet: record length, client hello length, total extensions length, PSK extension length, total identity length, and identity length contain their maximum value which is 2^16. The identity data field of the PSK extension of the packet contains the attack data, to be stored in the undefined memory (RAM) of the server. The size of the data is about 65 kB. Possibly the attacker can perform a remote code execution attack.

Vulnerability class: Buffer Overflow

EPSS: 0.088 (94.6th percentile) — read the EPSS interpretation.

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.

Affected products

  • Wolfssl — versions 4.0
  • N/a — versions n/a

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2019-11873?
CVE-2019-11873 is a critical-severity vulnerability in Wolfssl, classified under Out-of-bounds Write. CVSS score: 9.8/10. Published 2019-05-23.
How severe is CVE-2019-11873?
Critical severity. CVSS v3 base score is 9.8 out of 10.