PKCS#1 v1.5 Signature Verification Vulnerability in axTLS

CVE-2018-16253 · MEDIUM Severity

AV:N/AC:M/AU:N/C:N/I:P/A:N

In sig_verify() in x509.c in axTLS version 2.1.3 and before, the PKCS#1 v1.5 signature verification does not properly verify the ASN.1 metadata. Consequently, a remote attacker can forge signatures when small public exponents are being used, which could lead to impersonation through fake X.509 certificates. This is an even more permissive variant of CVE-2006-4790 and CVE-2014-1568.

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