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Fencer Vulns
critical 9.8

CVE-2016-4303 json

The parse_string function in cjson.c in the cJSON library mishandles UTF8/16 strings, which allows remote attackers to cause a denial of se…

published 2016-09-26 10 y ago modified 2026-06-17 4 mo ago also EUVD-2016-5303

cvss
9.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
7.0%
EPSS 7.0% chance of exploitation in 30 days, percentile 94%
public exploits
0
none known

Summary

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.

Patch / fix

  • es iperf3 3.0.12, 3.1.3
  • iperf3 Debian 14, Debian 13, Debian 12 3.1.3-1

debian advisories DEBIAN-CVE-2016-4303

  • iperf3 Ubuntu Pro 16.04 LTS 3.0.11-1ubuntu0.1~esm1

ubuntu advisories UBUNTU-CVE-2016-4303

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • iperf openSUSE Tumbleweed 3.1.3-1.3
  • iperf Package Hub 12 3.1.3-6.1

opensuse advisories openSUSE-SU-2024:10145-1openSUSE-SU-2016:2113-1openSUSE-SU-2016:2121-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2016-4303 updated cvss 5.1

iperf3: JSON parsing vulnerability

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

6.96% chance of exploitation in the next 30 days, higher than 94% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • talosintelligence.com http://www.talosintelligence.com/reports/TALOS-2016-0164/ referenced PoC, tagged "exploit" by a source, unverified
  • blog.talosintel.com http://blog.talosintel.com/2016/06/esnet-vulnerability.html referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 7.5 AV:N/AC:L/Au:N/C:P/I:P/A:P

Classification

Weakness
  • CWE-120 Buffer Copy without Checking Size of Input

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.