CVE-2026-3549 Details
Description
Heap Overflow in TLS 1.3 ECH parsing. An integer underflow existed in ECH extension parsing logic when calculating a buffer length, which resulted in writing beyond the bounds of an allocated buffer. Note that in wolfSSL, ECH is off by default, and the ECH standard is still evolving.
A heap overflow vulnerability has been identified in wolfSSL's implementation of TLS 1.3, specifically in the parsing of the Encrypted Client Hello (ECH) extension. This vulnerability arises from an integer underflow in the ECH extension parsing logic, which leads to a buffer length calculation error. As a result, data can be written beyond the limits of an allocated buffer, creating a potential security risk. It is important to note that ECH is disabled by default in wolfSSL, and the ECH standard is still being developed.
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 24, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://github.com/wolfSSL/wolfssl/pull/9817 | [email protected] | Issue TrackingPatch |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-122 | Heap-based Buffer Overflow | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| wolfssl wolfssl | < 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] |