CVE-2016-0639

Exploitation likely. EPSS gives it a 10% chance of exploitation in the next 30 days. A vendor fix is available.

CVSS 3.09.8Critical EPSS percentile96th10% chance in 30 days CISA KEVNot listedNo confirmed exploitation
No public exploit known FixVendor fixNo build named by the sources

Published 2016-04-21Updated 2026-05-06Sources: CVE.org, NVD, BDU

NVD CVE.org

What to do

The vendor has published a fix. Version details are below where the sources state them.

Oracle MysqlAffected: ≥ 5.6.0, ≤ 5.6.29Upgrade to: after 5.6.29Stated by: NVD

Versions as the sources state them. Full version matrix after sign-in

Steps

Written by AI from the record

Check the MySQL server version with your hosting provider or by running mysql --version.
Upgrade the 5.6 branch to 5.6.30 or later, or the 5.7 branch to 5.7.12 or later.
Until upgraded, limit database network access to known application servers and administrators.
Ask your IT provider to confirm the update completed and that database backups still restore correctly.

Vendor advisory Some work to apply

Check it yourselfA free OpenVAS check exists for this CVE. Run it against your hosts.Is your organisation exposed?Request an assessment to establish which checks fit your systems.

What it is

From the CVE record

Unspecified vulnerability in Oracle MySQL 5.6.29 and earlier and 5.7.11 and earlier allows remote attackers to affect confidentiality, integrity, and availability via vectors related to Pluggable Authentication.

In plain language

Written by AI from the record

MySQL 5.6.29 and earlier or 5.7.11 and earlier has a serious remote-access flaw, so a typical small business using those versions should update it promptly.

Unauthenticated remote compromise is possible in Oracle MySQL’s Pluggable Authentication component, with potential confidentiality, integrity, and availability impact.

If you're affected

Database data exposure
Unauthorized data changes
Database service outage
Business application disruption

What is it

This is a flaw in the part of MySQL that handles certain ways users and systems prove who they are. It is like a faulty lock on a records room: someone connecting over the network may be able to get at, alter, or disrupt the records without being given a key.

Who is affected

This matters to you if you run MySQL as the database behind a website, business application, or internal system. It applies to MySQL 5.6.29 and earlier and MySQL 5.7.11 and earlier, and is only a risk where an attacker can reach the database over the network.

How urgent is it

Attackers can target this remotely without a login, making exposed older MySQL servers a meaningful concern. There is no confirmed active exploitation and no public exploit code on record, so treat this as an amber priority: schedule the upgrade promptly and restrict access in the meantime.

What to do — in detail

Confirm the deployed server version with mysql --version, your operating-system package manager, or the database service inventory. For the 5.6 branch, target MySQL 5.6.30 or later; for the 5.7 branch, target MySQL 5.7.12 or later. Test the upgrade against a backup or staging instance first, particularly any custom Pluggable Authentication configuration; no specific breaking-change information is provided in the findings. If patching is delayed, allow inbound MySQL connections only from required application hosts and administrator networks, rather than exposing the database broadly. CISA has not added this CVE to KEV, so no CISA remediation due date applies. After the change, review database authentication and connection logs for unexpected remote sources, failed authentication attempts, new accounts, or unusual configuration changes.

Technical context

CVE-2016-0639 is rated CVSS 3.0 9.8 Critical (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H). It is an unspecified vulnerability in Oracle MySQL’s Pluggable Authentication component, reachable over the network with no privileges or user interaction required; preconditions are unknown. It is not listed in CISA KEV and no public exploit code is on record. EPSS estimates a 10.2% exploitation likelihood at the 95th percentile, with a falling trend; this is predictive, not evidence of exploitation.

This is a general assessment based on public vulnerability data. It does not account for your specific infrastructure — when in doubt, consult a security specialist.

Exploitation

Where each signal puts this CVE on the scale from published to confirmed exploited.

EPSS96th

CISA KEV

Not in the catalog. CISA has not confirmed exploitation.

Public exploits

No public exploit or proof of concept found in the sources we track.

EPSS

10% chance of exploitation activity in the next 30 days, which ranks it in the 96th percentile of scored CVEs.

Exploit Prediction Scoring System, FIRST.org. A probability, not a confirmation.

Lifecycle

22 events over 3807 days, from the signal feeds we watch.

2026-09-23EPSS band change0 → moderateepss band change
2026-09-21EPSS band changemoderate → 0epss band change
2026-09-06EPSS band change0 → moderateepss band change
2026-09-05EPSS band changemoderate → 0epss band change
2026-08-31EPSS band change0 → moderateepss band change
2026-08-29EPSS band changemoderate → low

Affected products

Oracle Corp.commercial · USaka oracle
- MySQLDatabaseOn-premDatabases / relational
redhatcommercial · USaka red hat
- enterprise linuxOSOn-premOperating Systems / linux-distro

And 2 more affected products. See all after sign-in

Technical detail

CVSS 3.0 vector

Open in the CVSS calculator

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Scored 9.8 by NVD.

How it is reached

Attack Vector NetworkExploitable remotely over the network without any special conditions
Attack Complexity LowNo special conditions — the attack can be reliably reproduced
Privileges Required NoneNo authentication required — anyone can exploit this
User Interaction NoneNo user interaction needed — fully automated exploitation

Scope

Scope UnchangedImpact is limited to the vulnerable component itself

Impact if exploited

Confidentiality HighTotal information disclosure — all data in the component is compromised
Integrity HighTotal loss of integrity — attacker can modify any data in the component
Availability HighTotal denial of service — the component is completely unavailable

Weaknesses

NVD-CWE-noinfoNo name in the record

Sources

References in the record

And 4 more references. See all after sign-in

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