CVE-2026-3849

UNKNOWN 0.0

Buffer Overflow in HPKE via Oversized ECH Config

CVSS Score

0.0

EPSS Score

0.4%

EPSS Percentile

59th

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.

CWE	CWE-787
Vendor	wolfssl inc.
Product	wolfssl
Published	Mar 19, 2026
Last Updated	Mar 25, 2026

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Affected Versions

wolfSSL Inc. / wolfSSL

v5.6.0-stable ≤ v5.8.4-stable

References

NVD ↗ CVE.org ↗ EPSS Data ↗

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

Credits

Haruto Kimura (Stella)