CVE-2026-3547

No indexed exploits for CVE-2026-3547 yet

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.

Affected products: Apache Httpd, Bind, Haproxy, Hitch, Jni, Lighty, Nginx, Curl
Wolfssl: < 5.9.0

Fix: Available
CVSS 3.1: 7.5 HIGH
EPSS: 0.3% (17th percentile)
Weakness: CWE-125
NVD status: Analyzed
Published: 2026-03-19

Fix

apply the fix in wolfssl/wolfssl#9859 (or upgrade to a release that includes it).

Workaround

build without ALPN support if ALPN is not required.

CVE-2026-3547 at NVD

Authoritative description, scoring and affected products

No exploit for CVE-2026-3547 has been indexed yet. Our index is built from live traffic and upstream syncs, so this page can only say what it knows — not that no exploit exists.