What is CVE-2016-0736?

CVE-2016-0736 is a high-severity vulnerability in Apache HTTP Server, classified under Cryptographic Issues. CVSS score: 7.5/10. Published 2017-07-27.

How severe is CVE-2016-0736?

High severity. CVSS v3 base score is 7.5 out of 10.

Is CVE-2016-0736 known to be exploited?

5 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Vulnerability in Apache HTTP Server

CVE-2016-0736

In Apache HTTP Server versions 2.4.0 to 2.4.23, mod_session_crypto was encrypting its data/cookie using the configured ciphers with possibly either CBC or ECB modes of operation (AES256-CBC by default), hence no selectable or builtin authenticated encryption. This made it vulnerable to padding oracle attacks, particularly with CBC.

Vulnerability class: POODLE (CVE-2014-3566)

Published 2017-07-27 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N.

EPSS exploit prediction

EPSS: 0.490 (98.8th percentile), scored 2026-09-30.

Moderate probability of exploitation in the next 30 days — watch for active exploitation reports. 99th percentile — 98.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.490 · newest: 0.490 · change: 0.000

Affected products

Apache HTTP Server — versions 2.4.0, 2.4.1, 2.4.2
Apache Software Foundation HTTP Server — versions 2.4.0 to 2.4.23

Weakness classification (CWE)

CWE-310 — Cryptographic Issues

Public proof-of-concept exploits

References

support.apple.com/HT208221
www.debian.org/security/2017/dsa-3796 (vendor-advisory)
www.exploit-db.com/exploits/40961/ (exploit)
www.securitytracker.com/id/1037508 (VDB Entry, Third Party Advisory, vdb-entry)
access.redhat.com/errata/RHSA-2017:1413 (vendor-advisory)
access.redhat.com/errata/RHSA-2017:1161 (vendor-advisory)
www.tenable.com/security/tns-2017-04
access.redhat.com/errata/RHSA-2017:1414 (vendor-advisory)
h20566.www2.hpe.com/hpsc/doc/public/display (Third Party Advisory)
www.securityfocus.com/bid/95078 (VDB Entry, Third Party Advisory, vdb-entry)

Frequently asked questions

What is CVE-2016-0736?: CVE-2016-0736 is a high-severity vulnerability in Apache HTTP Server, classified under Cryptographic Issues. CVSS score: 7.5/10. Published 2017-07-27.
How severe is CVE-2016-0736?: High severity. CVSS v3 base score is 7.5 out of 10.
Is CVE-2016-0736 known to be exploited?: 5 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.