CVE-2026-3849 | THREATINT

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.

PUBLISHED Reserved 2026-03-09 | Published 2026-03-19 | Updated 2026-03-25 | Assigner wolfSSL

MEDIUM: 6.9CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N/V:D/RE:M/U:Amber

Problem types

CWE-787: Out-of-bounds Write

Product status

Default status

unaffected

v5.6.0-stable (git)

affected

Credits

Haruto Kimura (Stella) finder

References

github.com/wolfSSL/wolfssl/pull/9737

cve.org (CVE-2026-3849)

nvd.nist.gov (CVE-2026-3849)

Download JSON