CVE-2026-3849 Details
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.
A stack buffer overflow vulnerability has been identified in wolfSSL version 5.8.4, specifically within the Encrypted Client Hello (ECH) support. This vulnerability arises when a maliciously crafted ECH configuration is processed, potentially leading to remote code execution and causing the client program to crash. The issue can be exploited by a malicious TLS server that supports ECH. It is important to note that ECH is disabled by default and only enabled with the 'enable-ech' option.
Metrics
CVSS 4.0 Severity and Vector Strings:
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed Mar 25, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://github.com/wolfSSL/wolfssl/pull/9737 | [email protected] | Issue TrackingPatch |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-787 | Out-of-bounds Write | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| wolfssl wolfssl | >= 5.6.0, < 5.9.0 |
CPE
Remediation
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Change History
4 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jun 17, 2026 | CVE Modified | [email protected] |
| Jun 17, 2026 | CVE Modified | CISA-ADP |
| Mar 26, 2026 | Initial Analysis | [email protected] |
| Mar 19, 2026 | New CVE Received | [email protected] |