CVE-2026-3549

CRITICAL

wolfSSL < 5.9.0 - Heap Buffer Overflow in TLS 1.3 ECH Parsing

Title source: manual

Description

Heap Overflow in TLS 1.3 ECH parsing. An integer underflow existed in ECH extension parsing logic when calculating a buffer length, which resulted in writing beyond the bounds of an allocated buffer. Note that in wolfSSL, ECH is off by default, and the ECH standard is still evolving.

Scores

CVSS v3 9.8
EPSS 0.0003
EPSS Percentile 7.3%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Details

CWE
CWE-122
Status published
Products (2)
wofSSL/wolfSSL < 5.9.0
wolfssl/wolfssl < 5.9.0
Published Mar 19, 2026
Tracked Since Mar 20, 2026