What’s Vulnerable › Vulnerabilities
CVE-2026-3549: ECH parsing heap buffer overflow
- Severity: critical (CVSS 9.8 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.5% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2026-03-19 · updated 2026-06-17
- Weakness: CWE-122
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 products
- wolfSSL: before 5.9.0 — fixed in 5.9.0
How to fix
Upgrade to a fixed version: wolfSSL 5.9.0. Check the vendor advisory for mitigations.
References
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