PuTTY Heap-Based Buffer Underflow Vulnerability in modmul Function

CVE-2013-4206 · MEDIUM Severity

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

Heap-based buffer underflow in the modmul function in sshbn.c in PuTTY before 0.63 allows remote SSH servers to cause a denial of service (crash) and possibly trigger memory corruption or code execution via a crafted DSA signature, which is not properly handled when performing certain bit-shifting operations during modular multiplication.

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