Information disclosure in Openssl

CVE-2016-0703

The get_client_master_key function in s2_srvr.c in the SSLv2 implementation in OpenSSL before 0.9.8zf, 1.0.0 before 1.0.0r, 1.0.1 before 1.0.1m, and 1.0.2 before 1.0.2a accepts a nonzero CLIENT-MASTER-KEY CLEAR-KEY-LENGTH value for an arbitrary cipher, which allows man-in-the-middle attackers to determine the MASTER-KEY value and decrypt TLS ciphertext data by leveraging a Bleichenbacher RSA padding oracle, a related issue to CVE-2016-0800.

Vulnerability class: Information Disclosure

EPSS: 0.054 (91.8th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 5.9 (Medium). Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N.

Affected products

  • Openssl — versions 1.0.0, 1.0.0a, 1.0.0b
  • N/a — versions n/a

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2016-0703?
CVE-2016-0703 is a medium-severity vulnerability in Openssl, classified under Information Disclosure. CVSS score: 5.9/10. Published 2016-03-02.
How severe is CVE-2016-0703?
Medium severity. CVSS v3 base score is 5.9 out of 10.
Is CVE-2016-0703 known to be exploited?
28 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.