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CVE-2016-5768

34
FAUCET Score

CVE-2016-5768 is a critical double free vulnerability in the _php_mb_regex_ereg_replace_exec function within the mbstring extension of PHP versions before 5.5.37, 5.6.23, and 7.0.8. This flaw allows remote attackers to execute arbitrary code or cause a denial of service through a callback exception. With a CVSS score of 9.8 (CRITICAL), it presents a severe risk due to its network-based attack vector, low attack complexity, and high impact on confidentiality, integrity, and availability. Despite its high severity, there is no evidence of active exploitation, no known public exploit code (Metasploit, Nuclei, ExploitDB), and minimal community discussion or media coverage.

Impacted Technologies

VendorProductVersion(s)CPE
<= 5.5.36CPE matchmatch criteria
cpe:2.3:a:php:php:*:*:*:*:*:*:*:*
5.6.0CPE matchmatch criteria
cpe:2.3:a:php:php:5.6.0:alpha1:*:*:*:*:*:*
5.6.0CPE matchmatch criteria
cpe:2.3:a:php:php:5.6.0:alpha2:*:*:*:*:*:*
5.6.0CPE matchmatch criteria
cpe:2.3:a:php:php:5.6.0:alpha3:*:*:*:*:*:*
5.6.0CPE matchmatch criteria
cpe:2.3:a:php:php:5.6.0:alpha4:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.0

9.8CRITICAL

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

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
3.9
Impact Score
5.9
CvssVersion
3.0

Exploit Intelligence

EPSS Score
9.63%
Probability of exploitation in next 30 days
EPSS Percentile
95.0%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0963 is in the 90th percentile among its peer group of 36,835 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.3 Bluesky, 0.3 Mastodon, and 2.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (21)

redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 7Fixed in: php-0:5.4.16-42.el7
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Software Collections for Red Hat Enterprise Linux 6Fixed in: rh-php56-0:2.3-1.el6
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Software Collections for Red Hat Enterprise Linux 6Fixed in: rh-php56-php-0:5.6.25-1.el6
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Software Collections for Red Hat Enterprise Linux 6Fixed in: rh-php56-php-pear-1:1.9.5-4.el6
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Software Collections for Red Hat Enterprise Linux 6.7 EUSFixed in: rh-php56-0:2.3-1.el6
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Software Collections for Red Hat Enterprise Linux 6.7 EUSFixed in: rh-php56-php-0:5.6.25-1.el6
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Software Collections for Red Hat Enterprise Linux 6.7 EUSFixed in: rh-php56-php-pear-1:1.9.5-4.el6
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Software Collections for Red Hat Enterprise Linux 7Fixed in: rh-php56-0:2.3-1.el7
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Software Collections for Red Hat Enterprise Linux 7Fixed in: rh-php56-php-0:5.6.25-1.el7
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Software Collections for Red Hat Enterprise Linux 7Fixed in: rh-php56-php-pear-1:1.9.5-4.el7
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Software Collections for Red Hat Enterprise Linux 7.2 EUSFixed in: rh-php56-0:2.3-1.el7
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Software Collections for Red Hat Enterprise Linux 7.2 EUSFixed in: rh-php56-php-0:5.6.25-1.el7
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Software Collections for Red Hat Enterprise Linux 7.2 EUSFixed in: rh-php56-php-pear-1:1.9.5-4.el7
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Software Collections for Red Hat Enterprise Linux 7.3 EUSFixed in: rh-php56-0:2.3-1.el7
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Software Collections for Red Hat Enterprise Linux 7.3 EUSFixed in: rh-php56-php-0:5.6.25-1.el7
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Software Collections for Red Hat Enterprise Linux 7.3 EUSFixed in: rh-php56-php-pear-1:1.9.5-4.el7
View patch
redhatend of lifevia redhat_api
Product: Red Hat Enterprise Linux 5Fixed in: php
redhatend of lifevia redhat_api
Product: Red Hat Enterprise Linux 5Fixed in: php53
redhatend of lifevia redhat_api
Product: Red Hat Enterprise Linux 6Fixed in: php
redhatend of lifevia redhat_api
Product: Red Hat Software CollectionsFixed in: php54-php
redhatend of lifevia redhat_api
Product: Red Hat Software CollectionsFixed in: php55-php

Vendor Advisories (1)

redhatCVE-2016-5768Low

php: Double free in _php_mb_regex_ereg_replace_exec

Jun 23, 2016

References

github.com / php/php-src/commit/5b597a2e5b28e2d5a52fc1be13f425f08f47cb62
lists.apple.com / archives/security-announce/2016/Sep/msg00006.html
lists.opensuse.org / opensuse-security-announce/2016-07/msg00004.html
lists.opensuse.org / opensuse-updates/2016-08/msg00003.html
php.net / ChangeLog-5.php
PatchRelease Notes
php.net / ChangeLog-7.php
Release Notes
rhn.redhat.com / errata/RHSA-2016-2598.html
rhn.redhat.com / errata/RHSA-2016-2750.html
bugs.php.net / bug.php
ExploitVendor Advisory
h20566.www2.hpe.com / portal/site/hpsc/public/kb/docDisplay
support.apple.com / HT207170
debian.org / security/2016/dsa-3618
openwall.com / lists/oss-security/2016/06/23/4
Release Notes
securityfocus.com / bid/91396