Is CVE-2016-4303 in the CISA KEV catalog?

No. CVE-2016-4303 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2016-4303?

CVE-2016-4303 has a CVSS v3 base score of 9.8 (CRITICAL).

What is the EPSS score for CVE-2016-4303?

CVE-2016-4303 has an EPSS score of 6.96% (93th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2016-4303?

Upgrade iperf3 on debian 11 to 3.1.3-1 or later. Fixes are available for 2 affected products.

CVE & CISA-KEV Catalog

CVE-2016-4303

CRITICALEPSS 93th pctl

9.8

CVSS v3

NVD

Description

The parse_string function in cjson.c in the cJSON library mishandles UTF8/16 strings, which allows remote attackers to cause a denial of service (crash) or execute arbitrary code via a non-hex character in a JSON string, which triggers a heap-based buffer overflow.

CWE-120Classic Buffer Overflow

How to fix

Remediation Available

iperf3Debian

Fixed in:3.1.3-1CVE-2016-4303

iperf3Ubuntu

Fixed in:3.0.11-1ubuntu0.1~esm1USN-4788-1

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Exploit Intelligence

6.96%probability of exploitation in 30 days

93rdpercentile

High risk: more likely to be exploited than 93% of all known CVEs.

References

Patch1

github.com

Exploit2

Third-Party Advisory5

Related Vulnerabilities

Other CWE-120 (Classic Buffer Overflow) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2014-0195	Medium	6.8	100%	-	Fix
CVE-2017-7269	Critical	9.8	100%	KEV	-
CVE-2019-11043	High	8.7	99%	KEV + Ransom	Fix
CVE-2011-4862	High	10.0	95%	-	Fix
CVE-2007-5659	High	7.8	94%	KEV	Fix
CVE-2022-3786	High	7.5	91%	-	Fix

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-05-06.