CVE-2020-26956

In some cases, removing HTML elements during sanitization would keep existing SVG event handlers and therefore lead to XSS. This vulnerability affects Firefox < 83, Firefox ESR < 78.5, and Thunderbird < 78.5.
Cross-site Scripting
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
NISTNIST
6.1 MEDIUM
NETWORK
LOW
NONE
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
mozillaCNA
---
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CVEADP
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Base Score
CVSS 3.x
EPSS Score
Percentile: 62%
VendorProductVersion
mozillafirefox
𝑥
< 83.0
mozillafirefox_esr
𝑥
< 78.5
mozillathunderbird
𝑥
< 78.5
𝑥
= Vulnerable software versions
Debian logo
Debian Releases
Debian Product
Codename
firefox
sid
132.0.1-1
fixed
firefox-esr
bullseye
115.14.0esr-1~deb11u1
fixed
bullseye (security)
128.4.0esr-1~deb11u1
fixed
bookworm
115.14.0esr-1~deb12u1
fixed
bookworm (security)
128.4.0esr-1~deb12u1
fixed
trixie
128.3.1esr-2
fixed
sid
128.4.0esr-1
fixed
thunderbird
bullseye
1:115.12.0-1~deb11u1
fixed
bullseye (security)
1:128.4.0esr-1~deb11u1
fixed
bookworm
1:115.12.0-1~deb12u1
fixed
bookworm (security)
1:128.4.0esr-1~deb12u1
fixed
sid
1:128.4.0esr-1
fixed
trixie
1:128.4.0esr-1
fixed
Ubuntu logo
Ubuntu Releases
Ubuntu Product
Codename
firefox
noble
Fixed 83.0+build2-0ubuntu1
released
mantic
Fixed 83.0+build2-0ubuntu1
released
lunar
Fixed 83.0+build2-0ubuntu1
released
kinetic
Fixed 83.0+build2-0ubuntu1
released
jammy
Fixed 83.0+build2-0ubuntu1
released
impish
Fixed 83.0+build2-0ubuntu1
released
hirsute
Fixed 83.0+build2-0ubuntu1
released
groovy
Fixed 83.0+build2-0ubuntu0.20.10.1
released
focal
Fixed 83.0+build2-0ubuntu0.20.04.1
released
bionic
Fixed 83.0+build2-0ubuntu0.18.04.2
released
xenial
Fixed 83.0+build2-0ubuntu0.16.04.3
released
trusty
dne
mozjs38
noble
dne
mantic
dne
lunar
dne
kinetic
dne
jammy
dne
impish
dne
hirsute
dne
groovy
dne
focal
dne
bionic
ignored
xenial
dne
trusty
dne
mozjs52
noble
dne
mantic
dne
lunar
dne
kinetic
dne
jammy
dne
impish
dne
hirsute
dne
groovy
ignored
focal
ignored
bionic
ignored
xenial
dne
trusty
dne
mozjs60
noble
dne
mantic
dne
lunar
dne
kinetic
dne
jammy
dne
impish
dne
hirsute
dne
groovy
dne
focal
dne
bionic
dne
xenial
dne
trusty
dne
mozjs68
noble
dne
mantic
dne
lunar
dne
kinetic
dne
jammy
dne
impish
dne
hirsute
dne
groovy
ignored
focal
ignored
bionic
dne
xenial
dne
trusty
dne
thunderbird
noble
Fixed 1:78.5.0+build3-0ubuntu1
released
mantic
Fixed 1:78.5.0+build3-0ubuntu1
released
lunar
Fixed 1:78.5.0+build3-0ubuntu1
released
kinetic
Fixed 1:78.5.0+build3-0ubuntu1
released
jammy
Fixed 1:78.5.0+build3-0ubuntu1
released
impish
Fixed 1:78.5.0+build3-0ubuntu1
released
hirsute
Fixed 1:78.5.0+build3-0ubuntu1
released
groovy
Fixed 1:78.5.0+build3-0ubuntu0.20.10.1
released
focal
Fixed 1:78.7.1+build1-0ubuntu0.20.04.1
released
bionic
Fixed 1:78.8.1+build1-0ubuntu0.18.04.1
released
xenial
ignored
trusty
dne
Common Weakness Enumeration
References
https://bugzilla.mozilla.org/show_bug.cgi?id=1666300
https://www.mozilla.org/security/advisories/mfsa2020-50/
https://www.mozilla.org/security/advisories/mfsa2020-51/
https://www.mozilla.org/security/advisories/mfsa2020-52/
https://bugzilla.mozilla.org/show_bug.cgi?id=1666300
https://www.mozilla.org/security/advisories/mfsa2020-50/
https://www.mozilla.org/security/advisories/mfsa2020-51/
https://www.mozilla.org/security/advisories/mfsa2020-52/