CVE-2026-3547
wolfSSL: out-of-bounds read (DoS) in ALPN parsing due to incomplete validation
Description
Out-of-bounds read in ALPN parsing due to incomplete validation. wolfSSL 5.8.4 and earlier contained an out-of-bounds read in ALPN handling when built with ALPN enabled (HAVE_ALPN / --enable-alpn). A crafted ALPN protocol list could trigger an out-of-bounds read, leading to a potential process crash (denial of service). Note that ALPN is disabled by default, but is enabled for these 3rd party compatibility features: enable-apachehttpd, enable-bind, enable-curl, enable-haproxy, enable-hitch, enable-lighty, enable-jni, enable-nginx, enable-quic.
INFO
Published Date :
March 19, 2026, 9:17 p.m.
Last Modified :
March 26, 2026, 6:27 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | HIGH | 50d2cd11-d01a-48ed-9441-5bfce9d63b27 | ||||
| CVSS 3.1 | HIGH | [email protected] |
Solution
- Update wolfSSL to version 5.8.5 or later.
- Ensure ALPN is disabled if not required.
- Review build configurations for ALPN enablement.
- Apply patches provided by the vendor.
Public PoC/Exploit Available at Github
CVE-2026-3547 has a 4 public
PoC/Exploit available at Github.
Go to the Public Exploits tab to see the list.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-3547.
| URL | Resource |
|---|---|
| https://github.com/wolfSSL/wolfssl/pull/9859 | Issue Tracking Patch |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-3547 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-3547
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
None
CMake Dockerfile Shell C++ C Makefile Euphoria Batchfile Linker Script BitBake
test
CMake Dockerfile Shell C++ C Makefile Euphoria Batchfile Linker Script BitBake
None
CMake Dockerfile Shell C++ C Makefile Euphoria Batchfile Linker Script BitBake
The wolfSSL library is a small, fast, portable implementation of TLS/SSL for embedded devices to the cloud. wolfSSL supports up to TLS 1.3 and DTLS 1.3!
ssl tls cryptography security openssl tls13 dtls https fips cryptography-api embedded-systems encryption iot trusted-execution-environment openssl-alternative c-library wolfssl cipher-suites openssl-api sniffer
C Shell Makefile Tcl Assembly C++ XS Perl C# M4
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-3547 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-3547 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Mar. 26, 2026
Action Type Old Value New Value Added CPE Configuration OR *cpe:2.3:a:wolfssl:wolfssl:*:*:*:*:*:*:*:* versions up to (excluding) 5.9.0 Added Reference Type wolfSSL Inc.: https://github.com/wolfSSL/wolfssl/pull/9859 Types: Issue Tracking, Patch -
New CVE Received by [email protected]
Mar. 19, 2026
Action Type Old Value New Value Added Description Out-of-bounds read in ALPN parsing due to incomplete validation. wolfSSL 5.8.4 and earlier contained an out-of-bounds read in ALPN handling when built with ALPN enabled (HAVE_ALPN / --enable-alpn). A crafted ALPN protocol list could trigger an out-of-bounds read, leading to a potential process crash (denial of service). Note that ALPN is disabled by default, but is enabled for these 3rd party compatibility features: enable-apachehttpd, enable-bind, enable-curl, enable-haproxy, enable-hitch, enable-lighty, enable-jni, enable-nginx, enable-quic. Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Added CWE CWE-125 Added Reference https://github.com/wolfSSL/wolfssl/pull/9859