How severe is CVE-2016-6620?

CVE-2016-6620 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2016-6620 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (87th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2016-6620?

CVE-2016-6620 primarily affects Phpmyadmin. In total, 60 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2016-6620?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2016-6620 published?

CVE-2016-6620 was published on 2016-12-11 and last updated on 2026-06-17.

CVE-2016-6620

CVE-2016-6620 is a critical-severity vulnerability in Phpmyadmin with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-502.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 3% (87th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-502
Affected product: Phpmyadmin
Published: 2016-12-11
Last modified: 2026-06-17

Description

An issue was discovered in phpMyAdmin. Some data is passed to the PHP unserialize() function without verification that it's valid serialized data. The unserialization can result in code execution because of the interaction with object instantiation and autoloading. All 4.6.x versions (prior to 4.6.4), 4.4.x versions (prior to 4.4.15.8), and 4.0.x versions (prior to 4.0.10.17) are affected.

Frequently asked questions

What is CVE-2016-6620?: An issue was discovered in phpMyAdmin. Some data is passed to the PHP unserialize() function without verification that it's valid serialized data. The unserialization can result in code execution because of the interaction with object instantiation and autoloading. All 4.6.x versions (prior to 4.6.4), 4.4.x versions (prior to 4.4.15.8), and 4.0.x versions (prior to 4.0.10.17) are affected.
How severe is CVE-2016-6620?: CVE-2016-6620 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2016-6620 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (87th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2016-6620?: CVE-2016-6620 primarily affects Phpmyadmin. In total, 60 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2016-6620?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2016-6620 published?: CVE-2016-6620 was published on 2016-12-11 and last updated on 2026-06-17.

References

Affected products (60)

cpe:2.3:a:phpmyadmin:phpmyadmin:4.6.0:*:*:*:*:*:*:*
cpe:2.3:a:phpmyadmin:phpmyadmin:4.6.1:*:*:*:*:*:*:*
cpe:2.3:a:phpmyadmin:phpmyadmin:4.6.2:*:*:*:*:*:*:*
cpe:2.3:a:phpmyadmin:phpmyadmin:4.6.3:*:*:*:*:*:*:*
cpe:2.3:a:phpmyadmin:phpmyadmin:4.0.0:*:*:*:*:*:*:*
cpe:2.3:a:phpmyadmin:phpmyadmin:4.0.1:*:*:*:*:*:*:*
cpe:2.3:a:phpmyadmin:phpmyadmin:4.0.2:*:*:*:*:*:*:*
cpe:2.3:a:phpmyadmin:phpmyadmin:4.0.3:*:*:*:*:*:*:*
cpe:2.3:a:phpmyadmin:phpmyadmin:4.0.4:*:*:*:*:*:*:*
cpe:2.3:a:phpmyadmin:phpmyadmin:4.0.4.1:*:*:*:*:*:*:*
cpe:2.3:a:phpmyadmin:phpmyadmin:4.0.4.2:*:*:*:*:*:*:*
cpe:2.3:a:phpmyadmin:phpmyadmin:4.0.5:*:*:*:*:*:*:*
cpe:2.3:a:phpmyadmin:phpmyadmin:4.0.6:*:*:*:*:*:*:*
cpe:2.3:a:phpmyadmin:phpmyadmin:4.0.7:*:*:*:*:*:*:*
cpe:2.3:a:phpmyadmin:phpmyadmin:4.0.8:*:*:*:*:*:*:*
cpe:2.3:a:phpmyadmin:phpmyadmin:4.0.9:*:*:*:*:*:*:*
cpe:2.3:a:phpmyadmin:phpmyadmin:4.0.10:*:*:*:*:*:*:*
cpe:2.3:a:phpmyadmin:phpmyadmin:4.0.10.1:*:*:*:*:*:*:*
cpe:2.3:a:phpmyadmin:phpmyadmin:4.0.10.2:*:*:*:*:*:*:*
cpe:2.3:a:phpmyadmin:phpmyadmin:4.0.10.3:*:*:*:*:*:*:*
cpe:2.3:a:phpmyadmin:phpmyadmin:4.0.10.4:*:*:*:*:*:*:*
cpe:2.3:a:phpmyadmin:phpmyadmin:4.0.10.5:*:*:*:*:*:*:*
cpe:2.3:a:phpmyadmin:phpmyadmin:4.0.10.6:*:*:*:*:*:*:*
cpe:2.3:a:phpmyadmin:phpmyadmin:4.0.10.7:*:*:*:*:*:*:*
cpe:2.3:a:phpmyadmin:phpmyadmin:4.0.10.8:*:*:*:*:*:*:*
cpe:2.3:a:phpmyadmin:phpmyadmin:4.0.10.9:*:*:*:*:*:*:*
cpe:2.3:a:phpmyadmin:phpmyadmin:4.0.10.10:*:*:*:*:*:*:*
cpe:2.3:a:phpmyadmin:phpmyadmin:4.0.10.11:*:*:*:*:*:*:*
cpe:2.3:a:phpmyadmin:phpmyadmin:4.0.10.12:*:*:*:*:*:*:*
cpe:2.3:a:phpmyadmin:phpmyadmin:4.0.10.13:*:*:*:*:*:*:*
cpe:2.3:a:phpmyadmin:phpmyadmin:4.0.10.14:*:*:*:*:*:*:*
cpe:2.3:a:phpmyadmin:phpmyadmin:4.0.10.15:*:*:*:*:*:*:*
cpe:2.3:a:phpmyadmin:phpmyadmin:4.0.10.16:*:*:*:*:*:*:*
cpe:2.3:a:phpmyadmin:phpmyadmin:4.4.0:*:*:*:*:*:*:*
cpe:2.3:a:phpmyadmin:phpmyadmin:4.4.1:*:*:*:*:*:*:*
cpe:2.3:a:phpmyadmin:phpmyadmin:4.4.1.1:*:*:*:*:*:*:*
cpe:2.3:a:phpmyadmin:phpmyadmin:4.4.2:*:*:*:*:*:*:*
cpe:2.3:a:phpmyadmin:phpmyadmin:4.4.3:*:*:*:*:*:*:*
cpe:2.3:a:phpmyadmin:phpmyadmin:4.4.4:*:*:*:*:*:*:*
cpe:2.3:a:phpmyadmin:phpmyadmin:4.4.5:*:*:*:*:*:*:*

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