CVE-2016-6306

What it is

The certificate parser in OpenSSL before 1.0.1u and 1.0.2 before 1.0.2i might allow remote attackers to cause a denial of service (out-of-bounds read) via crafted certificate operations, related to s3_clnt.c and s3_srvr.c.

At a glance

Exploitability

Can be exploited over the network without logging in. High risk of service disruption.

Exploit odds

41.7% chance of exploitation in the next 30 days (EPSS). Higher than most.

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2016-09-26 19:59 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-17 00:50 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 41.7% in the next 30 days (EPSS).
• Severity: 5.9 MEDIUM (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2016-09-26 19:59 UTC

Last modified

2026-06-17 00:50 UTC

Exploit probability

41.7% · EPSS, next 30 days

Weakness

CWE-125 · Out-of-bounds read

Record status

Modified

Affected

• OpenSSL 1.0.1
• OpenSSL 1.0.1a
• OpenSSL 1.0.1b
• OpenSSL 1.0.1c
• OpenSSL 1.0.1d
• OpenSSL 1.0.1e
• OpenSSL 1.0.1f
• OpenSSL 1.0.1g

Attack profile CVSS 3.1 · 5.9

Attack vector

Network

Complexity

High

Privileges needed

None

User interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

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