CVE-2020-26966

mediumpriority · track · 26EPSS 0.014 · 71 %ileDEEUUS

grimoire priorityP3 · Track

Exploitable?

—

no known exploitation

Likely / severe?

1.35% (71st) EPSS

CVSS 4.3 · medium

Is it mine?

20 products

Check your exposure

Who says so?

4 sources

cnnvd · enisa_euvd · cert_bund · nvd

EPSS · scored 2026-10-27

Searching for a single word from the address bar caused an mDNS request to be sent on the local network searching for a hostname consisting of that string; resulting in an information leak. *Note: This issue only affected Windows operating systems. Other operating systems are unaffected.*. This vulnerability affects Firefox < 83, Firefox ESR < 78.5, and Thunderbird < 78.5.

cvss

Technical severity, 0–10. One row per scoring source.

6.5

010

base score 0–10 · higher = more severe · hover a vector to decode

v2.04.3mediumAV:N/AC:M/Au:N/C:P/I:N/A:Nprimary · NVD / NIST USexploitability 8.6 · impact 2.9

v3.16.5mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:Nprimary · NVD / NIST USexploitability 2.8 · impact 3.6

v3.16mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N/E:Usecondary · CVSS-BT (t0sche)

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-200USLLM-inferred

affected products (20)

Products and version ranges known to be affected.

Debian Linuxall versionscert_bundDEcpe:/o:debian:debian_linux:-
Gentoo Linuxall versionscert_bundDEcpe:/o:gentoo:linux:-
Mozilla Firefox <83all versionscert_bundDE
Mozilla Firefox ESR <78.5all versionscert_bundDE
Mozilla Thunderbird <78.5all versionscert_bundDE
Open Source Arch Linuxall versionscert_bundDEcpe:/o:archlinux:archlinux:-
Open Source CentOSall versionscert_bundDEcpe:/o:centos:centos:-
Oracle Linuxall versionscert_bundDEcpe:/o:oracle:linux:-
Red Hat Enterprise Linuxall versionscert_bundDEcpe:/o:redhat:enterprise_linux:-
SUSE Linuxall versionscert_bundDEcpe:/o:suse:suse_linux:-
Ubuntu Linuxall versionscert_bundDEcpe:/o:canonical:ubuntu_linux:-
Mozilla Firefox< 83cert_bundDE
Mozilla Firefox ESR< 78.5cert_bundDE
Mozilla Thunderbird< 78.5cert_bundDE
Mozilla Firefox≤ < 83enisa_euvdEU
Mozilla Firefox ESR≤ < 78.5enisa_euvdEU
Mozilla Thunderbird≤ < 78.5enisa_euvdEU
mozilla firefox< 83.0nvdUScpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*
mozilla firefox esr< 78.5nvdUScpe:2.3:a:mozilla:firefox_esr:*:*:*:*:*:*:*:*
mozilla thunderbird< 78.5nvdUScpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:*

advisories (1)

Vendor and ecosystem advisories describing this.

WID-SEC-W-2026-0337Mozilla Firefox und Thunderbird: Mehrere SchwachstellenDeutsch2020-11-17csaf · cert_bundDE
Ein entfernter, anonymer Angreifer kann mehrere Schwachstellen in Mozilla Firefox, Mozilla Firefox ESR, Mozilla Thunderbird ausnutzen, um beliebigen Programmcode mit Benutzerrechten auszuführen, den Speicher zu korrumpieren, Daten zu manipulieren, vertrauliche Daten einzusehen, Sicherheitsmechanismen zu umgehen oder einen Cross Site Scripting Angriff durchzuführen.

also known as (3)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd cert_bund nvd NVD CVE.org MITRE

published 2020-12-09modified 2026-06-17

references (22)

External citations — patches, advisories, analysis.

scry

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