CVE-2016-4071

CVE-2016-4071 is a critical-severity vulnerability in Php with a CVSS 3.x base score of 9.8. Its EPSS exploit-prediction score of 19% places it in the 97th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-20.

Key facts

• Severity: Critical (CVSS 3.x base score 9.8)
• CVSS v2: 7.5
• EPSS exploit prediction: 19% (97th percentile)
• Actively exploited: Not listed in CISA KEV
• Weakness: CWE-20
• Affected product: Php
• Published: 2016-05-20
• Last modified: 2026-06-17

Description

Format string vulnerability in the php_snmp_error function in ext/snmp/snmp.c in PHP before 5.5.34, 5.6.x before 5.6.20, and 7.x before 7.0.5 allows remote attackers to execute arbitrary code via format string specifiers in an SNMP::get call.

Frequently asked questions

What is CVE-2016-4071?

Format string vulnerability in the php_snmp_error function in ext/snmp/snmp.c in PHP before 5.5.34, 5.6.x before 5.6.20, and 7.x before 7.0.5 allows remote attackers to execute arbitrary code via format string specifiers in an SNMP::get call.

How severe is CVE-2016-4071?

CVE-2016-4071 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-2016-4071 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 19% (97th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2016-4071?

CVE-2016-4071 primarily affects Php. In total, 79 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2016-4071?

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-2016-4071 published?

CVE-2016-4071 was published on 2016-05-20 and last updated on 2026-06-17.

References

• http://lists.apple.com/archives/security-announce/2016/May/msg00004.html
• http://lists.opensuse.org/opensuse-security-announce/2016-05/msg00031.html
• http://lists.opensuse.org/opensuse-security-announce/2016-05/msg00033.html
• http://lists.opensuse.org/opensuse-security-announce/2016-05/msg00056.html
• http://rhn.redhat.com/errata/RHSA-2016-2750.html
• http://www.debian.org/security/2016/dsa-3560
• http://www.openwall.com/lists/oss-security/2016/04/24/1
• http://www.php.net/ChangeLog-5.php
• http://www.php.net/ChangeLog-7.php
• http://www.securityfocus.com/bid/85800
• http://www.ubuntu.com/usn/USN-2952-1
• http://www.ubuntu.com/usn/USN-2952-2
• https://bugs.php.net/bug.php?id=71704
• https://git.php.net/?p=php-src.git%3Ba=commit%3Bh=6e25966544fb1d2f3d7596e060ce9c9269bbdcf8
• https://h20566.www2.hpe.com/portal/site/hpsc/public/kb/docDisplay?docId=emr_na-c05240731
• https://h20566.www2.hpe.com/portal/site/hpsc/public/kb/docDisplay?docId=emr_na-c05320149
• https://h20566.www2.hpe.com/portal/site/hpsc/public/kb/docDisplay?docId=emr_na-c05390722
• https://security.gentoo.org/glsa/201611-22
• https://support.apple.com/HT206567
• https://www.exploit-db.com/exploits/39645/

Affected products (79)

• cpe:2.3:a:php:php:5.6.0:alpha1:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.6.0:alpha2:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.6.0:alpha3:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.6.0:alpha4:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.6.0:alpha5:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.6.0:beta1:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.6.0:beta2:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.6.0:beta3:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.6.0:beta4:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.6.1:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.6.2:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.6.3:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.6.4:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.6.5:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.6.6:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.6.7:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.6.8:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.6.9:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.6.10:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.6.11:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.6.12:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.6.13:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.6.14:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.6.15:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.6.16:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.6.17:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.6.18:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.6.19:*:*:*:*:*:*:*
• cpe:2.3:o:apple:mac_os_x:*:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.5.0:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.5.0:alpha1:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.5.0:alpha2:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.5.0:alpha3:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.5.0:alpha4:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.5.0:alpha5:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.5.0:alpha6:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.5.0:beta1:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.5.0:beta2:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.5.0:beta3:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.5.0:beta4:*:*:*:*:*:*

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Threat intelligence

Threat-intel indicators referencing this CVE:

• 183.182.99.92 (ipv4-addr)
• 103.153.190.105 (ipv4-addr)
• 188.44.20.32 (ipv4-addr)
• 36.95.228.227 (ipv4-addr)
• 198.199.94.79 (ipv4-addr)
• 122.3.106.113 (ipv4-addr)