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2.3
wolfSSL Misinterprets Malformed Certificate Data in Some Configurations
CVE-2026-5188
Summary
In certain cases, wolfSSL may incorrectly process X.509 certificates with intentionally malformed data. This can happen when using the default configuration. To avoid potential issues, review your wolfSSL configuration to ensure the newer ASN.1 parsing implementation is enabled.
Original title
An integer underflow issue exists in wolfSSL when parsing the Subject Alternative Name (SAN) extension of X.509 certificates. A malformed certificate can specify an entry length larger than the enc...
Original description
An integer underflow issue exists in wolfSSL when parsing the Subject Alternative Name (SAN) extension of X.509 certificates. A malformed certificate can specify an entry length larger than the enclosing sequence, causing the internal length counter to wrap during parsing. This results in incorrect handling of certificate data. The issue is limited to configurations using the original ASN.1 parsing implementation which is off by default.
nvd CVSS4.0
2.3
Vulnerability type
CWE-191
Published: 10 Apr 2026 · Updated: 10 Apr 2026 · First seen: 10 Apr 2026