critical9.8
CVE-2026-3849
Stack Buffer Overflow in wc_HpkeLabeledExtract via Oversized ECH Config.
Impact
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.
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Wolfssl | Wolfssl | from 5.6.0 before 5.9.0 |