{"id":"CVE-2026-3849","summary":"Buffer Overflow in HPKE via Oversized ECH Config","details":"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.","modified":"2026-07-16T03:48:29.482921010Z","published":"2026-03-19T20:29:30.839Z","database_specific":{"cwe_ids":["CWE-787"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/3xxx/CVE-2026-3849.json","cna_assigner":"wolfSSL"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/3xxx/CVE-2026-3849.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-3849"},{"type":"FIX","url":"https://github.com/wolfSSL/wolfssl/pull/9737"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/wolfssl/wolfssl","events":[{"introduced":"979707380c677dfa65e3ba48f19e149773a4a32d"},{"fixed":"922d04b3568c6428a9fb905ddee3ef5a68db3108"}],"database_specific":{"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"],"cpe":"cpe:2.3:a:wolfssl:wolfssl:*:*:*:*:*:*:*:*"}}],"versions":["v5.8.4-stable","wolfEntropy2d","v5.8.2-stable","wolfEntropy1","v5.8.0-stable","v5.7.6-stable","v5.7.4-stable","v5.2.1","v5.7.2-stable","v5.7.0-stable","v5.6.6-stable","v5.6.4-stable","v5.6.2-stable","v5.6.3-stable","v5.6.0-stable"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-3849.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V4","score":"CVSS: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"}]}