CVE-2026-3549
9.8
CRITICAL
CVSS 3.1
EPSS 0.03%
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.
How to fix CVE-2026-3549
No fixed version has been published yet. Mitigate by removing the affected package or applying upstream guidance from the references below.
- Debian/wolfssl—no fix listed
Is CVE-2026-3549 being exploited?
Low — EPSS is 0.0%, meaning exploitation activity has not been observed at scale.
Affected packages (1)
- from 0
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | CRITICAL9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |