How severe is CVE-2016-6294?

CVE-2016-6294 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-2016-6294 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 6% (92nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2016-6294?

CVE-2016-6294 primarily affects Php. In total, 40 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2016-6294?

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-2016-6294 published?

CVE-2016-6294 was published on 2016-07-25 and last updated on 2026-06-17.

CVE-2016-6294

CVE-2016-6294 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. The underlying weakness is classified as CWE-125.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 6% (92nd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-125
Affected product: Php
Published: 2016-07-25
Last modified: 2026-06-17

Description

The locale_accept_from_http function in ext/intl/locale/locale_methods.c in PHP before 5.5.38, 5.6.x before 5.6.24, and 7.x before 7.0.9 does not properly restrict calls to the ICU uloc_acceptLanguageFromHTTP function, which allows remote attackers to cause a denial of service (out-of-bounds read) or possibly have unspecified other impact via a call with a long argument.

Frequently asked questions

What is CVE-2016-6294?: The locale_accept_from_http function in ext/intl/locale/locale_methods.c in PHP before 5.5.38, 5.6.x before 5.6.24, and 7.x before 7.0.9 does not properly restrict calls to the ICU uloc_acceptLanguageFromHTTP function, which allows remote attackers to cause a denial of service (out-of-bounds read) or possibly have unspecified other impact via a call with a long argument.
How severe is CVE-2016-6294?: CVE-2016-6294 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-2016-6294 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 6% (92nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2016-6294?: CVE-2016-6294 primarily affects Php. In total, 40 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2016-6294?: 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-2016-6294 published?: CVE-2016-6294 was published on 2016-07-25 and last updated on 2026-06-17.

References

Affected products (40)

cpe:2.3:a:php:php:*:*:*:*:*:*:*:*
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:a:php:php:5.6.20:*:*:*:*:*:*:*
cpe:2.3:a:php:php:5.6.21:*:*:*:*:*:*:*
cpe:2.3:a:php:php:5.6.22:*:*:*:*:*:*:*
cpe:2.3:a:php:php:5.6.23:*:*:*:*:*:*:*
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:a:php:php:7.0.8:*:*:*:*:*:*:*

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Other CWE-125 (Out-of-bounds Read) vulnerabilities

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CVE-2021-41556 — Critical (CVSS 10.0): sqclass.cpp in Squirrel through 2.2.5 and 3.x through 3.1 allows an out-of-bounds read (in the core interpreter) that…
CVE-2021-21777 — Critical (CVSS 10.0): An information disclosure vulnerability exists in the Ethernet/IP UDP handler functionality of EIP Stack Group OpENer…
CVE-2017-14451 — Critical (CVSS 10.0): An exploitable out-of-bounds read vulnerability exists in libevm (Ethereum Virtual Machine) of CPP-Ethereum. A…
CVE-2013-0767 — Critical (CVSS 10.0): The nsSVGPathElement::GetPathLengthScale function in Mozilla Firefox before 18.0, Firefox ESR 10.x before 10.0.12 and…

Browse all CWE-125 (Out-of-bounds Read) vulnerabilities →

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)
116.255.252.44 (ipv4-addr)