CVE-2026-3547: wolfSSL: out-of-bounds read (DoS) in ALPN parsing due to incomplete validation
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 (HAVEALPN / --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 Software
Remediation
Information
Patch Available
Event History
Frequently Asked Questions
What is the severity of CVE-2026-3547?
CVE-2026-3547 is classified as a high severity vulnerability due to the potential for denial of service through an out-of-bounds read.
How do I fix CVE-2026-3547?
To fix CVE-2026-3547, upgrade wolfSSL to version 5.8.5 or later where the issue has been addressed.
What versions of wolfSSL are affected by CVE-2026-3547?
CVE-2026-3547 affects wolfSSL versions 5.8.4 and earlier when ALPN is enabled.
What specific issue does CVE-2026-3547 exploit?
CVE-2026-3547 exploits an out-of-bounds read during ALPN parsing due to incomplete validation.
Can CVE-2026-3547 lead to other security impacts?
While primarily a denial of service vulnerability, CVE-2026-3547 may also enable further exploitation depending on the application context.