CVE-2026-3547
High
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.
SeverityHigh
CVSS7.5
Exploit probability—
ProductWolfssl
PublishedMar 19, 2026
First seenMar 19, 2026
Weakness typeCWE-125Out-of-bounds read
How to fix
Update
- wolfssl wolfssl5.9.0 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| wolfssl wolfssl | v < 5.9.0 | 5.9.0 |
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