CVE-2020-26976: debian debian_linux
Vulnerability summary
CVE-2020-26976 is a medium (CVSS 6.5) vulnerability in debian debian_linux. EPSS estimates a 1.64% chance of exploitation in the next 30 days, higher than 76% of scored vulnerabilities.
Advisory lineage
Upstream 0 · Downstream 28 · Related 14Timeline
- 07-01-2021PublishedVulnerability first disclosed.
- 04-08-2024Last modifiedVulnerability information updated.
Description
When a HTTPS pages was embedded in a HTTP page, and there was a service worker registered for the former, the service worker could have intercepted the request for the secure page despite the iframe not being a secure context due to the (insecure) framing. This vulnerability affects Firefox < 84.
CVSS metrics
4 scores · 3 sources · 2 versions- OSV · UbuntuEcosystem advisory · calculated6.5MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
- OSV · DebianEcosystem advisory · calculated6.5MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
EPSS trend
Probability
1.64%
Chance of exploitation in the next 30 days
Percentile
76%
Versus all other CVEs
30-day change
+0.02 pp
From 1.62% on 19-09-2026
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeNo weakness data has been published for this record.
Affected systems
Ubuntu6 products
- firefox< 84.0+build3-0ubuntu0.16.04.1 | < 84.0+build3-0ubuntu0.18.04.1 | < 84.0+build3-0ubuntu0.20.04.1
- mozjs38All versions (No fix recorded)
- mozjs52All versions (No fix recorded)
- mozjs68All versions (No fix recorded)
- mozjs78All versions (No fix recorded)
Debian3 products
- firefox-esr< 78.7.0esr-1
- thunderbird< 1:78.7.0-1
- debian_linuxEOL9.0 | 10.0
Mozilla1 product
- firefox≥ unspecified, < 84 | < 84.0
3 vendors · 10 products
References
14 links- bugzilla.mozilla.org/show_bug.cgi?id=1674343X Refsource MISCIssue TrackingPermissions RequiredVendor Advisory
- lists.debian.org/debian-lts-announce/2021/02/msg00002.htmlMailing ListX Refsource MLISTThird Party Advisory
- lists.debian.org/debian-lts-announce/2021/02/msg00001.htmlMailing ListX Refsource MLISTThird Party Advisory