CVE-2020-26967
When listening for page changes with a Mutation Observer, a malicious web page could confuse...
6.5 MediumFix available
When listening for page changes with a Mutation Observer, a malicious web page could confuse Firefox Screenshots into interacting with elements other than those that it injected into the page. This would lead to internal errors and unexpected behavior in the Screenshots code. This vulnerability affects Firefox < 83.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- Required
What an attacker can affect
- Confidentiality
- None
- Integrity
- High
- Availability
- None
Exploit likelihood
0.85%Up 0.2 points since Apr 14, 2021
What each source reports
NVD Score used
When listening for page changes with a Mutation Observer, a malicious web page could confuse Firefox Screenshots into interacting with elements other than those that it injected into the page. This would lead to internal errors and unexpected behavior in the Screenshots code. This vulnerability affects Firefox < 83.
- Record
CVE-2020-26967- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N - CVSS 2.0
- 4.3 Medium
AV:N/AC:M/Au:N/C:N/I:P/A:N - Updated
- 2026-11-02
CVE List No score
When listening for page changes with a Mutation Observer, a malicious web page could confuse Firefox Screenshots into interacting with elements other than those that it injected into the page. This would lead to internal errors and unexpected behavior in the Screenshots code. This vulnerability affects Firefox < 83.
- Record
CVE-2020-26967- Updated
- 2026-11-02
EUVDEUVD-2020-19491 No score
When listening for page changes with a Mutation Observer, a malicious web page could confuse Firefox Screenshots into interacting with elements other than those that it injected into the page. This would lead to internal errors and unexpected behavior in the Screenshots code. This vulnerability affects Firefox < 83.
- Record
EUVD-2020-19491- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-g4xj-2594-cc4j No score
When listening for page changes with a Mutation Observer, a malicious web page could confuse...
When listening for page changes with a Mutation Observer, a malicious web page could confuse Firefox Screenshots into interacting with elements other than those that it injected into the page. This would lead to internal errors and unexpected behavior in the Screenshots code. This vulnerability affects Firefox < 83.
- Record
GHSA-g4xj-2594-cc4j- Updated
- 2026-11-02
OSVALPINE-CVE-2020-26967
When listening for page changes with a Mutation Observer, a malicious web page could confuse Firefox Screenshots into interacting with elements other than those that it injected into the page. This would lead to internal errors and unexpected behavior in the Screenshots code. This vulnerability affects Firefox < 83.
- Record
ALPINE-CVE-2020-26967- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N - Updated
- 2026-11-03
OSVUBUNTU-CVE-2020-26967
When listening for page changes with a Mutation Observer, a malicious web page could confuse Firefox Screenshots into interacting with elements other than those that it injected into the page. This would lead to internal errors and unexpected behavior in the Screenshots code. This vulnerability affects Firefox < 83.
- Record
UBUNTU-CVE-2020-26967- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N - Updated
- 2026-11-02
Show 4 moreShow less
OSVopenSUSE-SU-2024:10600-1 No score
MozillaFirefox-92.0-1.2 on GA media
These are all security issues fixed in the MozillaFirefox-92.0-1.2 package on the GA media of openSUSE Tumbleweed.
- Record
openSUSE-SU-2024:10600-1- Updated
- 2026-11-02
OSVopenSUSE-SU-2024:14572-1 No score
firefox-esr-128.5.1-1.1 on GA media
These are all security issues fixed in the firefox-esr-128.5.1-1.1 package on the GA media of openSUSE Tumbleweed.
- Record
openSUSE-SU-2024:14572-1- Updated
- 2026-11-02
OSVUSN-4637-1 No score
firefox vulnerabilities
Multiple security issues were discovered in Firefox. If a user were tricked in to opening a specially crafted website, an attacker could potentially exploit these to cause a denial of service, obtain sensitive information across origins, bypass security restrictions, conduct phishing attacks, conduct cross-site scripting (XSS) attacks, bypass Content Security Policy (CSP) restrictions, conduct DNS rebinding attacks, or execute arbitrary code.
- Record
USN-4637-1- Updated
- 2026-11-02
OSVUSN-4637-2 No score
firefox vulnerabilities
USN-4637-1 fixed vulnerabilities in Firefox. This update provides the corresponding updates for Ubuntu 16.04 LTS.
Original advisory details:
Multiple security issues were discovered in Firefox. If a user were tricked in to opening a specially crafted website, an attacker could potentially exploit these to cause a denial of service, obtain sensitive information across origins, bypass security restrictions, conduct phishing attacks, conduct cross-site scripting (XSS) attacks, bypass Content Security Policy (CSP) restrictions, conduct DNS rebinding attacks, or execute arbitrary code.
- Record
USN-4637-2- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
firefoxAlpine:v3.12 |
before 83.0-r0 | 83.0-r0 |
firefoxAlpine:v3.13 |
before 83.0-r0 | 83.0-r0 |
firefoxAlpine:v3.14 |
before 83.0-r0 | 83.0-r0 |
firefoxAlpine:v3.15 |
before 83.0-r0 | 83.0-r0 |
firefoxAlpine:v3.16 |
before 83.0-r0 | 83.0-r0 |
firefoxAlpine:v3.17 |
before 83.0-r0 | 83.0-r0 |
firefoxAlpine:v3.18 |
before 83.0-r0 | 83.0-r0 |
firefoxAlpine:v3.19 |
before 83.0-r0 | 83.0-r0 |
firefoxAlpine:v3.20 |
before 83.0-r0 | 83.0-r0 |
firefoxAlpine:v3.21 |
before 83.0-r0 | 83.0-r0 |
Show 18 moreShow less
| Package | Affected | Fixed |
|---|---|---|
firefoxAlpine:v3.22 |
before 83.0-r0 | 83.0-r0 |
firefoxAlpine:v3.23 |
before 83.0-r0 | 83.0-r0 |
librewolfAlpine:v3.21 |
before 83.0-r0 | 83.0-r0 |
librewolfAlpine:v3.22 |
before 83.0-r0 | 83.0-r0 |
librewolfAlpine:v3.23 |
before 83.0-r0 | 83.0-r0 |
librewolfAlpine:v3.24 |
before 83.0-r0 | 83.0-r0 |
firefoxUbuntu:16.04:LTS |
before 83.0+build2-0ubuntu0.16.04.3, plus listed versions 41.0.2+build2-0ubuntu142.0+build2-0ubuntu144.0+build3-0ubuntu244.0.1+build1-0ubuntu144.0.2+build1-0ubuntu1 Show 45 moreShow less45.0+build2-0ubuntu145.0.1+build1-0ubuntu145.0.2+build1-0ubuntu146.0+build5-0ubuntu0.16.04.246.0.1+build1-0ubuntu0.16.04.247.0+build3-0ubuntu0.16.04.148.0+build2-0ubuntu0.16.04.149.0+build4-0ubuntu0.16.04.149.0.2+build2-0ubuntu0.16.04.250.0+build2-0ubuntu0.16.04.250.0.2+build1-0ubuntu0.16.04.150.1.0+build2-0ubuntu0.16.04.151.0.1+build2-0ubuntu0.16.04.151.0.1+build2-0ubuntu0.16.04.252.0+build2-0ubuntu0.16.04.152.0.1+build2-0ubuntu0.16.04.152.0.2+build1-0ubuntu0.16.04.153.0+build6-0ubuntu0.16.04.153.0.2+build1-0ubuntu0.16.04.253.0.3+build1-0ubuntu0.16.04.254.0+build3-0ubuntu0.16.04.155.0.1+build2-0ubuntu0.16.04.255.0.2+build1-0ubuntu0.16.04.156.0+build6-0ubuntu0.16.04.156.0+build6-0ubuntu0.16.04.257.0+build4-0ubuntu0.16.04.557.0+build4-0ubuntu0.16.04.657.0.1+build2-0ubuntu0.16.04.157.0.3+build1-0ubuntu0.16.04.157.0.4+build1-0ubuntu0.16.04.158.0+build6-0ubuntu0.16.04.158.0.1+build1-0ubuntu0.16.04.158.0.2+build1-0ubuntu0.16.04.159.0+build5-0ubuntu0.16.04.159.0.1+build1-0ubuntu0.16.04.159.0.2+build1-0ubuntu0.16.04.159.0.2+build1-0ubuntu0.16.04.360.0+build2-0ubuntu0.16.04.160.0.1+build2-0ubuntu0.16.04.160.0.2+build1-0ubuntu0.16.04.161.0+build3-0ubuntu0.16.04.261.0.1+build1-0ubuntu0.16.04.162.0+build2-0ubuntu0.16.04.362.0+build2-0ubuntu0.16.04.462.0+build2-0ubuntu0.16.04.5 |
83.0+build2-0ubuntu0.16.04.3 |
firefoxUbuntu:18.04:LTS |
before 83.0+build2-0ubuntu0.18.04.2, plus listed versions 56.0+build6-0ubuntu157.0.1+build2-0ubuntu159.0.1+build1-0ubuntu159.0.2+build1-0ubuntu160.0+build2-0ubuntu1 Show 45 moreShow less60.0.1+build2-0ubuntu0.18.04.160.0.2+build1-0ubuntu0.18.04.161.0+build3-0ubuntu0.18.04.161.0.1+build1-0ubuntu0.18.04.162.0+build2-0ubuntu0.18.04.362.0+build2-0ubuntu0.18.04.462.0+build2-0ubuntu0.18.04.562.0.3+build1-0ubuntu0.18.04.163.0+build2-0ubuntu0.18.04.263.0.3+build1-0ubuntu0.18.04.164.0+build3-0ubuntu0.18.04.165.0+build2-0ubuntu0.18.04.165.0.1+build2-0ubuntu0.18.04.166.0+build3-0ubuntu0.18.04.166.0.1+build1-0ubuntu0.18.04.166.0.2+build1-0ubuntu0.18.04.166.0.3+build1-0ubuntu0.18.04.166.0.4+build3-0ubuntu0.18.04.166.0.5+build1-0ubuntu0.18.04.167.0+build2-0ubuntu0.18.04.167.0.1+build1-0ubuntu0.18.04.167.0.2+build2-0ubuntu0.18.04.167.0.3+build1-0ubuntu0.18.04.167.0.4+build1-0ubuntu0.18.04.168.0+build3-0ubuntu0.18.04.168.0.1+build1-0ubuntu0.18.04.168.0.2+build1-0ubuntu0.18.04.169.0+build2-0ubuntu0.18.04.169.0.1+build1-0ubuntu0.18.04.169.0.2+build1-0ubuntu0.18.04.170.0+build2-0ubuntu0.18.04.170.0.1+build1-0ubuntu0.18.04.171.0+build5-0ubuntu0.18.04.172.0.1+build1-0ubuntu0.18.04.172.0.2+build1-0ubuntu0.18.04.173.0+build3-0ubuntu0.18.04.173.0.1+build1-0ubuntu0.18.04.174.0+build3-0ubuntu0.18.04.174.0.1+build1-0ubuntu0.18.04.175.0+build3-0ubuntu0.18.04.176.0+build2-0ubuntu0.18.04.176.0.1+build1-0ubuntu0.18.04.177.0.1+build1-0ubuntu0.18.04.178.0.1+build1-0ubuntu0.18.04.178.0.2+build2-0ubuntu0.18.04.1 |
83.0+build2-0ubuntu0.18.04.2 |
mozjs52Ubuntu:18.04:LTS |
All versions, plus listed versions 52.3.1-0ubuntu352.3.1-7fakesync152.8.1-0ubuntu0.18.04.152.9.1-0ubuntu0.18.04.1 |
None known |
mozjs38Ubuntu:18.04:LTS |
All versions, plus listed versions 38.8.0~repack1-0ubuntu138.8.0~repack1-0ubuntu338.8.0~repack1-0ubuntu4 |
None known |
firefoxUbuntu:20.04:LTS |
before 83.0+build2-0ubuntu0.20.04.1, plus listed versions 69.0.3+build1-0ubuntu170.0+build2-0ubuntu170.0+build2-0ubuntu270.0.1+build1-0ubuntu271.0+build2-0ubuntu2 Show 25 moreShow less71.0+build5-0ubuntu172.0.1+build1-0ubuntu172.0.2+build1-0ubuntu173.0+build1-0ubuntu173.0+build2-0ubuntu173.0+build3-0ubuntu173.0.1+build1-0ubuntu174.0+build1-0ubuntu174.0+build2-0ubuntu174.0+build2-0ubuntu274.0+build3-0ubuntu175.0+build3-0ubuntu176.0+build2-0ubuntu0.20.04.176.0.1+build1-0ubuntu0.20.04.177.0.1+build1-0ubuntu0.20.04.178.0.1+build1-0ubuntu0.20.04.178.0.2+build2-0ubuntu0.20.04.179.0+build1-0ubuntu0.20.04.180.0+build2-0ubuntu0.20.04.180.0.1+build1-0ubuntu0.20.04.181.0+build2-0ubuntu0.20.04.181.0.2+build1-0ubuntu0.20.04.182.0+build2-0ubuntu0.20.04.182.0.2+build1-0ubuntu0.20.04.182.0.3+build1-0ubuntu0.20.04.1 |
83.0+build2-0ubuntu0.20.04.1 |
mozjs68Ubuntu:20.04:LTS |
All versions, plus listed versions 68.5.0-1~fakesync68.5.0-2~fakesync68.6.0-168.6.0-1ubuntu1 |
None known |
mozjs52Ubuntu:20.04:LTS |
All versions, plus listed versions 52.9.1-1build152.9.1-1ubuntu3 |
None known |
firefoxUbuntu:18.04:LTS From an advisory covering 15 CVEs |
before 83.0+build2-0ubuntu0.18.04.2, plus listed versions 56.0+build6-0ubuntu157.0.1+build2-0ubuntu159.0.1+build1-0ubuntu159.0.2+build1-0ubuntu160.0+build2-0ubuntu1 Show 45 moreShow less60.0.1+build2-0ubuntu0.18.04.160.0.2+build1-0ubuntu0.18.04.161.0+build3-0ubuntu0.18.04.161.0.1+build1-0ubuntu0.18.04.162.0+build2-0ubuntu0.18.04.362.0+build2-0ubuntu0.18.04.462.0+build2-0ubuntu0.18.04.562.0.3+build1-0ubuntu0.18.04.163.0+build2-0ubuntu0.18.04.263.0.3+build1-0ubuntu0.18.04.164.0+build3-0ubuntu0.18.04.165.0+build2-0ubuntu0.18.04.165.0.1+build2-0ubuntu0.18.04.166.0+build3-0ubuntu0.18.04.166.0.1+build1-0ubuntu0.18.04.166.0.2+build1-0ubuntu0.18.04.166.0.3+build1-0ubuntu0.18.04.166.0.4+build3-0ubuntu0.18.04.166.0.5+build1-0ubuntu0.18.04.167.0+build2-0ubuntu0.18.04.167.0.1+build1-0ubuntu0.18.04.167.0.2+build2-0ubuntu0.18.04.167.0.3+build1-0ubuntu0.18.04.167.0.4+build1-0ubuntu0.18.04.168.0+build3-0ubuntu0.18.04.168.0.1+build1-0ubuntu0.18.04.168.0.2+build1-0ubuntu0.18.04.169.0+build2-0ubuntu0.18.04.169.0.1+build1-0ubuntu0.18.04.169.0.2+build1-0ubuntu0.18.04.170.0+build2-0ubuntu0.18.04.170.0.1+build1-0ubuntu0.18.04.171.0+build5-0ubuntu0.18.04.172.0.1+build1-0ubuntu0.18.04.172.0.2+build1-0ubuntu0.18.04.173.0+build3-0ubuntu0.18.04.173.0.1+build1-0ubuntu0.18.04.174.0+build3-0ubuntu0.18.04.174.0.1+build1-0ubuntu0.18.04.175.0+build3-0ubuntu0.18.04.176.0+build2-0ubuntu0.18.04.176.0.1+build1-0ubuntu0.18.04.177.0.1+build1-0ubuntu0.18.04.178.0.1+build1-0ubuntu0.18.04.178.0.2+build2-0ubuntu0.18.04.1 |
83.0+build2-0ubuntu0.18.04.2 |
firefoxUbuntu:20.04:LTS From an advisory covering 15 CVEs |
before 83.0+build2-0ubuntu0.20.04.1, plus listed versions 69.0.3+build1-0ubuntu170.0+build2-0ubuntu170.0+build2-0ubuntu270.0.1+build1-0ubuntu271.0+build2-0ubuntu2 Show 25 moreShow less71.0+build5-0ubuntu172.0.1+build1-0ubuntu172.0.2+build1-0ubuntu173.0+build1-0ubuntu173.0+build2-0ubuntu173.0+build3-0ubuntu173.0.1+build1-0ubuntu174.0+build1-0ubuntu174.0+build2-0ubuntu174.0+build2-0ubuntu274.0+build3-0ubuntu175.0+build3-0ubuntu176.0+build2-0ubuntu0.20.04.176.0.1+build1-0ubuntu0.20.04.177.0.1+build1-0ubuntu0.20.04.178.0.1+build1-0ubuntu0.20.04.178.0.2+build2-0ubuntu0.20.04.179.0+build1-0ubuntu0.20.04.180.0+build2-0ubuntu0.20.04.180.0.1+build1-0ubuntu0.20.04.181.0+build2-0ubuntu0.20.04.181.0.2+build1-0ubuntu0.20.04.182.0+build2-0ubuntu0.20.04.182.0.2+build1-0ubuntu0.20.04.182.0.3+build1-0ubuntu0.20.04.1 |
83.0+build2-0ubuntu0.20.04.1 |
firefoxUbuntu:16.04:LTS From an advisory covering 15 CVEs |
before 83.0+build2-0ubuntu0.16.04.3, plus listed versions 41.0.2+build2-0ubuntu142.0+build2-0ubuntu144.0+build3-0ubuntu244.0.1+build1-0ubuntu144.0.2+build1-0ubuntu1 Show 45 moreShow less45.0+build2-0ubuntu145.0.1+build1-0ubuntu145.0.2+build1-0ubuntu146.0+build5-0ubuntu0.16.04.246.0.1+build1-0ubuntu0.16.04.247.0+build3-0ubuntu0.16.04.148.0+build2-0ubuntu0.16.04.149.0+build4-0ubuntu0.16.04.149.0.2+build2-0ubuntu0.16.04.250.0+build2-0ubuntu0.16.04.250.0.2+build1-0ubuntu0.16.04.150.1.0+build2-0ubuntu0.16.04.151.0.1+build2-0ubuntu0.16.04.151.0.1+build2-0ubuntu0.16.04.252.0+build2-0ubuntu0.16.04.152.0.1+build2-0ubuntu0.16.04.152.0.2+build1-0ubuntu0.16.04.153.0+build6-0ubuntu0.16.04.153.0.2+build1-0ubuntu0.16.04.253.0.3+build1-0ubuntu0.16.04.254.0+build3-0ubuntu0.16.04.155.0.1+build2-0ubuntu0.16.04.255.0.2+build1-0ubuntu0.16.04.156.0+build6-0ubuntu0.16.04.156.0+build6-0ubuntu0.16.04.257.0+build4-0ubuntu0.16.04.557.0+build4-0ubuntu0.16.04.657.0.1+build2-0ubuntu0.16.04.157.0.3+build1-0ubuntu0.16.04.157.0.4+build1-0ubuntu0.16.04.158.0+build6-0ubuntu0.16.04.158.0.1+build1-0ubuntu0.16.04.158.0.2+build1-0ubuntu0.16.04.159.0+build5-0ubuntu0.16.04.159.0.1+build1-0ubuntu0.16.04.159.0.2+build1-0ubuntu0.16.04.159.0.2+build1-0ubuntu0.16.04.360.0+build2-0ubuntu0.16.04.160.0.1+build2-0ubuntu0.16.04.160.0.2+build1-0ubuntu0.16.04.161.0+build3-0ubuntu0.16.04.261.0.1+build1-0ubuntu0.16.04.162.0+build2-0ubuntu0.16.04.362.0+build2-0ubuntu0.16.04.462.0+build2-0ubuntu0.16.04.5 |
83.0+build2-0ubuntu0.16.04.3 |
MozillaFirefoxopenSUSE:Tumbleweed From an advisory covering 661 CVEs |
before 92.0-1.2 | 92.0-1.2 |
firefox-esropenSUSE:Tumbleweed From an advisory covering 1860 CVEs |
before 128.5.1-1.1 | 128.5.1-1.1 |
History
| Recorded | Changed | Sources |
|---|---|---|
| affected, facts | ||
| affected, aliases, references | OSV | |
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2020-26967 is a medium vulnerability (CVSS 6.5) in Mozilla Firefox, published November 17, 2020. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.85%, the 58th percentile. Fixed in firefox 83.0-r0.
References
bugzilla.mozilla.org/show_bug.cgi?id=1665820
mozilla.org/security/advisories/mfsa2020-50
nvd.nist.gov/vuln/detail/CVE-2020-26967
github.com/advisories/GHSA-g4xj-2594-cc4j
security.alpinelinux.org/vuln/CVE-2020-26967
ubuntu.com/security/CVE-2020-26967
Show 194 moreShow less
cve.org/CVERecord?id=CVE-2020-26967
suse.com/security/cve/CVE-2006-6077
lists.opensuse.org/archives/list/[email protected]/thread/3HI2RC7AJAHY74Q6MK7GNGWU6TITB22V
This page doesn't list everything
Left out here: 106 versions and 1,685 references. The JSON record has them.