CVE-2020-26956: mozilla firefox Cross-site Scripting
CVSS: 6.1v3.1MediumModified
AliasesUBUNTU-CVE-2020-26956DEBIAN-CVE-2020-26956
Published 09-12-2020Last modified 04-08-2024
Vulnerability summary
CVE-2020-26956 is a medium (CVSS 6.1) Cross-site Scripting vulnerability in mozilla firefox. EPSS estimates a 1.23% chance of exploitation in the next 30 days, higher than 68.5% of scored vulnerabilities.
CVSS score
6.1/10
010
Medium · v3.1 (NVD)EPSS score
1.23%
0%100%
Low · 0.00 pp in 30 daysKEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded
Advisory lineage
Upstream 0 · Downstream 33 · Related 15DLA-2457-1DLA-2464-1DSA-4793-1DSA-4796-1MGASA-2020-0427MGASA-2020-0433OPENSUSE-SU-2020:2020-1OPENSUSE-SU-2020:2031-1OPENSUSE-SU-2020:2096-1OPENSUSE-SU-2020:2187-1OPENSUSE-SU-2020:2315-1OPENSUSE-SU-2024:10600-1OPENSUSE-SU-2024:10601-1OPENSUSE-SU-2024:14572-1RHSA-2020:5231RHSA-2020:5232RHSA-2020:5233RHSA-2020:5234RHSA-2020:5235RHSA-2020:5236RHSA-2020:5237RHSA-2020:5238RHSA-2020:5239RHSA-2020:5240RHSA-2020:5257RHSA-2020:5314SUSE-SU-2020:14548-1SUSE-SU-2020:3383-1SUSE-SU-2020:3458-1SUSE-SU-2020:3528-1SUSE-SU-2020:3548-1USN-4637-1USN-4637-2
Timeline
- 09-12-2020PublishedVulnerability first disclosed.
- 04-08-2024Last modifiedVulnerability information updated.
Description
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.
CVSS metrics
4 scores · 3 sources · 2 versionsMedium 6.1Preferred score · NVD (NIST)
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:NSourcesAll 3 agree
- OSV · UbuntuEcosystem advisory · calculated6.1MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
- OSV · DebianEcosystem advisory · calculated6.1MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Medium 4.3Preferred score · NVD (NIST)
AV:N/AC:M/Au:N/C:N/I:P/A:NSourcesSingle source
EPSS trend
Probability
1.23%
Chance of exploitation in the next 30 days
Percentile
69%
Versus all other CVEs
30-day change
0.00 pp
From 1.23% on 19-09-2026
19-09-202619-10-2026
EPSS score1.23%
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Ubuntu5 products
- firefox< 83.0+build2-0ubuntu0.16.04.3 | < 83.0+build2-0ubuntu0.18.04.2 | < 83.0+build2-0ubuntu0.20.04.1
- mozjs38All versions (No fix recorded)
- mozjs52All versions (No fix recorded)
- mozjs68All versions (No fix recorded)
- thunderbird< 1:78.8.1+build1-0ubuntu0.18.04.1 | < 1:78.7.1+build1-0ubuntu0.20.04.1
Mozilla3 products
- firefox< 83 | < 83.0
- firefox_esr< 78.5
- thunderbird< 78.5
Debian2 products
- firefox-esr< 78.5.0esr-1
- thunderbird< 1:78.5.0-1
3 vendors · 10 products
References
12 links- bugzilla.mozilla.org/show_bug.cgi?id=1666300X Refsource MISCIssue TrackingPermissions RequiredVendor Advisory
