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_ids": [
"CWE-787"
],
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/3xxx/CVE-2026-3849.json",
"cna_assigner": "wolfSSL"
}{
"cpe": "cpe:2.3:a:wolfssl:wolfssl:*:*:*:*:*:*:*:*",
"extracted_events": [
{
"introduced": "v5.6.0-stable"
},
{
"last_affected": "v5.8.4-stable"
},
{
"introduced": "5.6.0"
},
{
"fixed": "5.9.0"
}
],
"source": [
"AFFECTED_FIELD",
"CPE_RANGE"
]
}