CVE-2011-4354

What it is

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.

At a glance

Exploitability

Can be exploited over the network without logging in. Limited direct impact.

Exploit odds

3.0% chance of exploitation in the next 30 days (EPSS).

Fix

No patch or advisory is linked yet. Look at mitigations or restrict exposure.

Timeline

1. 2012-01-27 00:55 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-16 23:34 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 3.0% in the next 30 days (EPSS).
• Severity: 5.8 MEDIUM (CVSS).
• Fix: none linked yet, which raises it.

Details

Published

2012-01-27 00:55 UTC

Last modified

2026-06-16 23:34 UTC

Exploit probability

3.0% · EPSS, next 30 days

Weakness

CWE-310

Record status

Modified

Affected

• OpenSSL ≤ 0.9.8g
• OpenSSL 0.9.1c
• OpenSSL 0.9.2b
• OpenSSL 0.9.3
• OpenSSL 0.9.3a
• OpenSSL 0.9.4
• OpenSSL 0.9.5
• OpenSSL 0.9.5a

Attack profile CVSS 2.0 · 5.8

Attack vector

Network

Complexity

Medium

Authentication

None

Confidentiality

Partial

Integrity

Partial

Availability

None

Is it in your code?

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