Vulnerability · Published Mar 19, 2026 · Assigned by wolfSSL
CVE-2026-3549ECH parsing heap buffer overflow
High 8.3
In plain English
A high-severity heap buffer overflow in wolfSSL from wofSSL. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 43% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS 4.0)8.3High
Exploit odds (30 days)0.5%top 56.6% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.23 | wolfssl | 5.9.1-r0 | ALPINE-CVE-2026-3549 |
| Alpine:v3.24 | wolfssl | 5.9.0-r0 | ALPINE-CVE-2026-3549 |
| Debian:12 | wolfssl | no fix listed | DEBIAN-CVE-2026-3549 |
| Debian:13 | wolfssl | no fix listed | DEBIAN-CVE-2026-3549 |
| Ubuntu:22.04:LTS | wolfssl | no fix listed | UBUNTU-CVE-2026-3549 |
| Ubuntu:24.04:LTS | wolfssl | no fix listed | UBUNTU-CVE-2026-3549 |
| Ubuntu:25.10 | wolfssl | no fix listed | UBUNTU-CVE-2026-3549 |
| Ubuntu:26.04:LTS | wolfssl | no fix listed | UBUNTU-CVE-2026-3549 |
| Ubuntu:26.10 | wolfssl | no fix listed | UBUNTU-CVE-2026-3549 |
Affected products (as reported)
Weakness: CWE-122 · Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:H/SC:L/SI:L/SA:L