How severe is CVE-2016-4541?

CVE-2016-4541 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-2016-4541 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 6% (93rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2016-4541?

CVE-2016-4541 primarily affects Php. In total, 30 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2016-4541?

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-2016-4541 published?

CVE-2016-4541 was published on 2016-05-22 and last updated on 2026-06-17.

CVE-2016-4541

CVE-2016-4541 is a critical-severity vulnerability in Php 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.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 6% (93rd percentile)
Actively exploited: Not listed in CISA KEV
Affected product: Php
Published: 2016-05-22
Last modified: 2026-06-17

Description

The grapheme_strpos function in ext/intl/grapheme/grapheme_string.c in PHP before 5.5.35, 5.6.x before 5.6.21, and 7.x before 7.0.6 allows remote attackers to cause a denial of service (out-of-bounds read) or possibly have unspecified other impact via a negative offset.

Frequently asked questions

What is CVE-2016-4541?: The grapheme_strpos function in ext/intl/grapheme/grapheme_string.c in PHP before 5.5.35, 5.6.x before 5.6.21, and 7.x before 7.0.6 allows remote attackers to cause a denial of service (out-of-bounds read) or possibly have unspecified other impact via a negative offset.
How severe is CVE-2016-4541?: CVE-2016-4541 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-2016-4541 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 6% (93rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2016-4541?: CVE-2016-4541 primarily affects Php. In total, 30 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2016-4541?: 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-2016-4541 published?: CVE-2016-4541 was published on 2016-05-22 and last updated on 2026-06-17.

References

Affected products (30)

cpe:2.3:o:fedoraproject:fedora:24:*:*:*:*:*:*:*
cpe:2.3:a:php:php:*:*:*:*:*:*:*:*
cpe:2.3:a:php:php:5.6.0:*:*:*:*:*:*:*
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:a:php:php:5.6.20:*:*:*:*:*:*:*
cpe:2.3:a:php:php:7.0.0:*:*:*:*:*:*:*
cpe:2.3:a:php:php:7.0.1:*:*:*:*:*:*:*
cpe:2.3:a:php:php:7.0.2:*:*:*:*:*:*:*
cpe:2.3:a:php:php:7.0.3:*:*:*:*:*:*:*
cpe:2.3:a:php:php:7.0.4:*:*:*:*:*:*:*
cpe:2.3:a:php:php:7.0.5:*:*:*:*:*:*:*
cpe:2.3:o:opensuse:leap:42.1:*:*:*:*:*:*:*

More vulnerabilities in Php

CVE-2015-0235 — Critical (CVSS 10.0): Heap-based buffer overflow in the __nss_hostname_digits_dots function in glibc 2.2, and other 2.x versions before 2.18,…
CVE-2012-2688 — Critical (CVSS 10.0): Unspecified vulnerability in the _php_stream_scandir function in the stream implementation in PHP before 5.3.15 and…
CVE-2012-2376 — Critical (CVSS 10.0): Buffer overflow in the com_print_typeinfo function in PHP 5.4.3 and earlier on Windows allows remote attackers to…
CVE-2011-3268 — Critical (CVSS 10.0): Buffer overflow in the crypt function in PHP before 5.3.7 allows context-dependent attackers to have an unspecified…
CVE-2009-4143 — Critical (CVSS 10.0): PHP before 5.2.12 does not properly handle session data, which has unspecified impact and attack vectors related to (1)…
CVE-2008-5557 — Critical (CVSS 10.0): Heap-based buffer overflow in ext/mbstring/libmbfl/filters/mbfilter_htmlent.c in the mbstring extension in PHP 4.3.0…

All CVEs affecting Php →

Threat intelligence

Threat-intel indicators referencing this CVE:

45.84.120.3 (ipv4-addr)
79.137.34.248 (ipv4-addr)
221.161.235.168 (ipv4-addr)
200.196.50.91 (ipv4-addr)
187.51.208.158 (ipv4-addr)
187.141.71.166 (ipv4-addr)
187.110.238.50 (ipv4-addr)
113.164.66.10 (ipv4-addr)