CVE-2016-6559

CRITICALNVD 9.89.8—
EchelonGraph scoreMEDIUM confidence

Score 9.8 from GitHub Security Advisory (severity: CRITICAL) published 2022-05-13. NVD baseline CVSS 9.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
9.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 4%CVSS: 9.8Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

Improper bounds checking of the obuf variable in the link_ntoa() function in linkaddr.c of the BSD libc library may allow an attacker to read or write from memory. The full impact and severity depends on the method of exploit and how the library is used by applications. According to analysis by FreeBSD developers, it is very unlikely that applications exist that utilize link_ntoa() in an exploitable manner, and the CERT/CC is not aware of any proof of concept. A blog post describes the functionality of link_ntoa() and points out that none of the base utilities use this function in an exploitable manner. For more information, please see FreeBSD Security Advisory SA-16:37.

CVSS v3
9.8
EG Score
9.8(medium)
EG Risk
50(Track)
EG Risk 50/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity98% × 45%
Exploitation4% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
4%
EPSS %ILE
89%
KEV
Not listed

Published

July 13, 2018

Last Modified

November 21, 2024

Advisory Details (4)

Auto-updated May 28, 2026
🔬 Proof of concept available. No patch confirmed yet. Sources: cert.
generic
https://www.securityfocus.com/bid/94694
cert🟡 PoC Available

VU#548487 - BSD libc contains a buffer overflow vulnerability in link_ntoa()

https://www.kb.cert.org/vuls/id/548487
generic
https://www.freebsd.org/security/advisories/FreeBSD-SA-16:37.libc.asc
generic
http://www.securitytracker.com/id/1037398

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 10× in last 7d / 40× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-26 14:50 UTCEPSS rescore
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  50. 2026-05-28 13:42 UTCEPSS rescore
  51. 2026-05-28 05:14 UTCEG score recompute
  52. 2026-05-28 05:14 UTCGHSA enrichment
  53. 2026-05-27 13:38 UTCEPSS rescore
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  57. 2026-05-26 07:17 UTCEPSS rescore
  58. 2026-05-24 16:44 UTCEPSS rescore

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2016-6559?
CVE-2016-6559 is a critical vulnerability published on July 13, 2018. Improper bounds checking of the obuf variable in the linkntoa() function in linkaddr.c of the BSD libc library may allow an attacker to read or write from memory. The full impact and severity depends on the method of exploit and how the library is used by applications. According to analysis by…
When was CVE-2016-6559 disclosed?
CVE-2016-6559 was first published in the National Vulnerability Database on July 13, 2018, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2016-6559 actively exploited?
CVE-2016-6559 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 4% probability of exploitation in the next 30 days, which ranks it in the top 11.4% of all scored CVEs.
What is the CVSS score of CVE-2016-6559?
CVE-2016-6559 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2016-6559?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2016-6559, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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