crypto/bn/bn_nist.c in OpenSSL before 0.9.8h on 32-bit platforms, as used in stunnel and other products, in certain circumstances involving ECDH or ECDHE cipher suites, uses an incorrect modular reduction algorithm in its implementation of the P-256 and P-384 NIST elliptic curves, which allows remote attackers to obtain the private key of a TLS server via multiple handshake attempts.
Severity
Medium 5.8
Published
27 Jan 2012
Last changed
16 Jun 2026
Added to UpHeron
21 Oct 2026
Exploit chance
3% in the next 30 daysHigher than 87% of CVEs. EPSS by FIRST, 12 Nov 2026