CVE-2026-3849CRITICAL 9.8EPSS p35.2%

CVE-2026-3849CVE-2026-3849

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.

Scoring

CVSS 3.19.8 (CRITICAL)
VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS0.44% probability of exploitation · percentile 35.2% · 2026-06-19T12:03:05Z
Published2026-03-19
Last modified2026-03-26

Underlying weaknesses· 1

CWE-787

References

  1. https://github.com/wolfSSL/wolfssl/pull/9737

1

TypeTargetConfidenceTier
WeaknessOut-of-bounds Writecwe-7870%live

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Sourced from NVD + FIRST.org EPSS. Curated for EU compliance use cases by Adam Lundqvist, Founder at SQUR.