No exploitation reportedFix available

CVE-2016-4537

No exploitation reported by the sources we read.

Published2016-05-22
WeaknessCWE-20

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

The bcpowmod function in ext/bcmath/bcmath.c in PHP before 5.5.35, 5.6.x before 5.6.21, and 7.x before 7.0.6 accepts a negative integer for the scale argument, which allows remote attackers to cause a denial of service or possibly have unspecified other impact via a crafted call.

Timeline

dates in UTC

2016-05-2201:59CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 21:37 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2016-4537?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2016-4537?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD

PHP

Branch	Affected	Fixed in	Source
5.5	≤ 5.5.34	no fix published	NVD
5.6	= 5.6.0	no fix published	NVD
5.6	= 5.6.1	no fix published	NVD
5.6	= 5.6.2	no fix published	NVD
5.6	= 5.6.3	no fix published	NVD
5.6	= 5.6.4	no fix published	NVD
5.6	= 5.6.5	no fix published	NVD
5.6	= 5.6.6	no fix published	NVD
5.6	= 5.6.7	no fix published	NVD
5.6	= 5.6.8	no fix published	NVD
5.6	= 5.6.9	no fix published	NVD
5.6	= 5.6.10	no fix published	NVD

Fedoraproject fedora

Branch	Affected	Fixed in	Source
24.x	= 24	no fix published	NVD

Opensuse leap

Branch	Affected	Fixed in	Source
42.1	= 42.1	no fix published	NVD

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

Advisories and patches

php.netPatch
php.netPatch

Detection

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: none listed

Sources

NVDCVSS 3.09.8read 2026-10-23
NVDCVSS 2.07.5read 2026-10-23
NVDweakness (CWE)CWE-20read 2026-10-23
FIRST EPSSEPSS score5.7 %2026-10-23

Technical details

CVSS v3 Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Published: 2016-05-22
Last Modified: 2026-06-17
NVD status: Modified

Frequently asked questions

What is CVE-2016-4537?

Is CVE-2016-4537 actively exploited?

Active exploitation of CVE-2016-4537 has not been confirmed. Its EPSS score was 5.7% on 2026-10-23, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2016-4537?

CVE-2016-4537 has a CVSS v3 base score of 9.8 (CRITICAL severity), with vector string CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

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