CVE-2026-3549
Critical
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.
SeverityCritical
CVSS9.8
Exploit probability—
ProductWolfssl
PublishedMar 19, 2026
First seenMar 19, 2026
Weakness typeCWE-122CWE-122
How to fix
Update
- wolfssl wolfssl5.9.0 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| wolfssl wolfssl | v < 5.9.0 | 5.9.0 |
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