Public proof of conceptFix available

CVE-2016-9066

Q: Is CVE-2016-9066 actively exploited?

Active exploitation of CVE-2016-9066 has not been confirmed. Its EPSS score was 12.0% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

Q: What is the CVSS score for CVE-2016-9066?

CVE-2016-9066 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

A public proof of concept exists; no exploitation attested.

Published2018-06-11
Fixed in50.0 · 45.5.0
WeaknessCWE-119

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

A buffer overflow resulting in a potentially exploitable crash due to memory allocation issues when handling large amounts of incoming data. This vulnerability affects Thunderbird < 45.5, Firefox ESR < 45.5, and Firefox < 50.

Timeline

dates in UTC

2018-06-1121:29CVE publishedNVD
2026-10-2319:23First public proof of conceptPoC-in-GitHub
2026-10-2319:23EPSS crossed 10 %FIRST EPSS

Observed activity

isMalicious corpus · updated 2026-10-23 18:48 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-2016-9066?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2016-9066?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD

Mozilla firefox

Branch	Affected	Fixed in	Source
50.0	< 50.0	50.0	NVD
45.5	< 45.5.0	45.5.0	NVD

Debian debian linux

Branch	Affected	Fixed in	Source
8.0	= 8.0	no fix published	NVD

Mozilla thunderbird

Branch	Affected	Fixed in	Source
45.5	< 45.5.0	45.5.0	NVD

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

Fix

Update Mozilla firefox to 50.0 · 45.5.0

Advisories and patches

bugzilla.mozilla.orgVendor Advisory
www.mozilla.orgVendor Advisory
www.mozilla.orgVendor Advisory
www.mozilla.orgVendor Advisory

Detection

read 2026-10-23 19:23 UTC

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: 1 repository, unverifiedsaelo/foxpwn

Sources

NVDCVSS 3.07.5read 2026-10-23
NVDCVSS 2.05read 2026-10-23
NVDweakness (CWE)CWE-119read 2026-10-23
FIRST EPSSEPSS score12.0 %read 2026-10-23
PoC-in-GitHubproof of concept1read 2026-10-23

Technical details

CVSS v3 Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Published: 2018-06-11
Last Modified: 2026-06-17
NVD status: Modified

Frequently asked questions

What is CVE-2016-9066?

Is CVE-2016-9066 actively exploited?

Active exploitation of CVE-2016-9066 has not been confirmed. Its EPSS score was 12.0% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2016-9066?

CVE-2016-9066 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

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