CVE-2026-3849

CRITICAL

9.8

Description

Stack Buffer Overflow in wc_HpkeLabeledExtract via Oversized ECH Config. A vulnerability existed in wolfSSL 5.8.4 ECH (Encrypted Client Hello) support, where a maliciously crafted ECH config could cause a stack buffer overflow on the client side, leading to potential remote execution and client program crash. This could be exploited by a malicious TLS server supporting ECH. Note that ECH is off by default, and is only enabled with enable-ech.

CVE Details

CVSS v3.1 Score9.8

SeverityCRITICAL

CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Attack VectorNETWORK

ComplexityLOW

Privileges RequiredNONE

User InteractionNONE

Published3/19/2026

Last Modified3/26/2026

Sourcenvd

Honeypot Sightings0

Affected Products

wolfssl:wolfssl

Weaknesses (CWE)

CWE-787

References

https://github.com/wolfSSL/wolfssl/pull/9737(facts@wolfssl.com)

IOC Correlations

No correlations recorded

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