CVE-2014-3566: SSL 3.0 CBC padding flaw enables POODLE cleartext recovery

Automated analysis

Generated by VULONE's analysis model from the NVD record, CISA KEV and EPSS data on 17 September 2026. Confidence: high.

medium priorityThe flaw is old and widely patched, but EPSS is near maximum and any remaining SSL 3.0 endpoint is trivially downgradeable, so residual exposure still warrants attention.

What it is

SSL 3.0 uses nondeterministic CBC padding, allowing a padding-oracle attack (POODLE) against connections that fall back to SSL 3.0. An attacker positioned in the network path can recover small amounts of cleartext, such as cookies or session tokens, from otherwise encrypted traffic. The issue affects OpenSSL through 1.0.1i and many other products that still permit SSL 3.0.

Impact

An attacker who can intercept traffic gains partial cleartext from the encrypted session, typically enough to steal session cookies and hijack authenticated sessions. The CVSS 3.1 score is only 3.4 (LOW) because confidentiality impact is limited and the attack requires a man-in-the-middle position plus user interaction.

Attack surface

Reached over the network by a man-in-the-middle who can force or observe an SSL 3.0 fallback; no authentication is required, but the CVSS vector includes UI:R, meaning some user interaction is needed to trigger the vulnerable connection. Any client or server that still negotiates SSL 3.0 is exposed.

Exploitation

Not listed in CISA KEV and no ransomware associations are recorded, but EPSS is 0.99999 (100th percentile), indicating very high predicted exploitation activity. All references are third-party advisories and vendor notices; none are tagged as exploit code.

What to do

• Disable SSL 3.0 on all servers and clients, or set the minimum protocol to TLS 1.0 or higher.
• Apply vendor patches and configuration updates for OpenSSL and the affected operating systems and products.
• Enable TLS_FALLBACK_SCSV where supported to prevent forced protocol downgrade.
• Audit and remove legacy applications and appliances that cannot negotiate TLS 1.1 or higher.
• Rotate session cookies and tokens that may have been exposed over SSL 3.0 connections.

Detection

• Search TLS/SSL logs and configuration scans for any endpoint still offering or negotiating SSL 3.0.
• Monitor for repeated TLS handshake failures or downgrade attempts that indicate padding-oracle probing.
• Alert on SSL 3.0 cipher suites appearing in network flow or IDS telemetry.
• Review proxy and load balancer logs for forced fallback patterns from clients to SSL 3.0.

This assessment is produced automatically and is not human-reviewed. Verify against the vendor advisory before acting on it.