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Vulnerability details: VCID-tvcx-7p64-7qe3
Vulnerability ID VCID-tvcx-7p64-7qe3
Aliases CVE-2020-26976
Summary 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.
Status Published
Exploitability 0.5
Weighted Severity 9.0
Risk 4.5
Affected and Fixed Packages Package Details
Weaknesses (1)
CWE-200 Exposure of Sensitive Information to an Unauthorized Actor
System Score Found at
cvssv3 6.1 https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2020-26976.json
epss 0.01056 https://api.first.org/data/v1/epss?cve=CVE-2020-26976
epss 0.01056 https://api.first.org/data/v1/epss?cve=CVE-2020-26976
epss 0.01056 https://api.first.org/data/v1/epss?cve=CVE-2020-26976
epss 0.01056 https://api.first.org/data/v1/epss?cve=CVE-2020-26976
epss 0.01056 https://api.first.org/data/v1/epss?cve=CVE-2020-26976
epss 0.01056 https://api.first.org/data/v1/epss?cve=CVE-2020-26976
epss 0.01056 https://api.first.org/data/v1/epss?cve=CVE-2020-26976
epss 0.01056 https://api.first.org/data/v1/epss?cve=CVE-2020-26976
epss 0.01056 https://api.first.org/data/v1/epss?cve=CVE-2020-26976
epss 0.01056 https://api.first.org/data/v1/epss?cve=CVE-2020-26976
epss 0.01056 https://api.first.org/data/v1/epss?cve=CVE-2020-26976
epss 0.01056 https://api.first.org/data/v1/epss?cve=CVE-2020-26976
epss 0.01056 https://api.first.org/data/v1/epss?cve=CVE-2020-26976
epss 0.01056 https://api.first.org/data/v1/epss?cve=CVE-2020-26976
epss 0.01056 https://api.first.org/data/v1/epss?cve=CVE-2020-26976
epss 0.01056 https://api.first.org/data/v1/epss?cve=CVE-2020-26976
epss 0.01056 https://api.first.org/data/v1/epss?cve=CVE-2020-26976
cvssv3.1 6.1 https://ftp.suse.com/pub/projects/security/yaml/suse-cvss-scores.yaml
cvssv2 4.3 https://nvd.nist.gov/vuln/detail/CVE-2020-26976
cvssv3.1 6.5 https://nvd.nist.gov/vuln/detail/CVE-2020-26976
archlinux High https://security.archlinux.org/AVG-1362
archlinux High https://security.archlinux.org/AVG-1496
generic_textual critical https://www.mozilla.org/en-US/security/advisories/mfsa2020-54
generic_textual high https://www.mozilla.org/en-US/security/advisories/mfsa2021-04
generic_textual high https://www.mozilla.org/en-US/security/advisories/mfsa2021-05
Reference id Reference type URL
https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2020-26976.json
https://api.first.org/data/v1/epss?cve=CVE-2020-26976
https://bugzilla.mozilla.org/show_bug.cgi?id=1674343
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-15685
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-16044
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-26976
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-23953
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-23954
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-23960
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-23964
https://ftp.suse.com/pub/projects/security/yaml/suse-cvss-scores.yaml
https://lists.debian.org/debian-lts-announce/2021/02/msg00001.html
https://lists.debian.org/debian-lts-announce/2021/02/msg00002.html
https://security.gentoo.org/glsa/202102-02
https://www.debian.org/security/2021/dsa-4840
https://www.debian.org/security/2021/dsa-4842
https://www.mozilla.org/security/advisories/mfsa2020-54/
1920649 https://bugzilla.redhat.com/show_bug.cgi?id=1920649
ASA-202012-25 https://security.archlinux.org/ASA-202012-25
ASA-202102-2 https://security.archlinux.org/ASA-202102-2
AVG-1362 https://security.archlinux.org/AVG-1362
AVG-1496 https://security.archlinux.org/AVG-1496
cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*
CVE-2020-26976 https://nvd.nist.gov/vuln/detail/CVE-2020-26976
mfsa2020-54 https://www.mozilla.org/en-US/security/advisories/mfsa2020-54
mfsa2021-04 https://www.mozilla.org/en-US/security/advisories/mfsa2021-04
mfsa2021-05 https://www.mozilla.org/en-US/security/advisories/mfsa2021-05
RHSA-2021:0285 https://access.redhat.com/errata/RHSA-2021:0285
RHSA-2021:0288 https://access.redhat.com/errata/RHSA-2021:0288
RHSA-2021:0289 https://access.redhat.com/errata/RHSA-2021:0289
RHSA-2021:0290 https://access.redhat.com/errata/RHSA-2021:0290
RHSA-2021:0297 https://access.redhat.com/errata/RHSA-2021:0297
RHSA-2021:0298 https://access.redhat.com/errata/RHSA-2021:0298
RHSA-2021:0299 https://access.redhat.com/errata/RHSA-2021:0299
RHSA-2021:0397 https://access.redhat.com/errata/RHSA-2021:0397
USN-4671-1 https://usn.ubuntu.com/4671-1/
USN-4736-1 https://usn.ubuntu.com/4736-1/
No exploits are available.
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N Found at https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2020-26976.json
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N Found at https://ftp.suse.com/pub/projects/security/yaml/suse-cvss-scores.yaml
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: AV:N/AC:M/Au:N/C:N/I:P/A:N Found at https://nvd.nist.gov/vuln/detail/CVE-2020-26976
Exploitability (E) Access Vector (AV) Access Complexity (AC) Authentication (Au) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

high

functional

unproven

proof_of_concept

not_defined

local

adjacent_network

network

high

medium

low

multiple

single

none

none

partial

complete

none

partial

complete

none

partial

complete
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N Found at https://nvd.nist.gov/vuln/detail/CVE-2020-26976
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Exploit Prediction Scoring System (EPSS)
Percentile 0.76684
EPSS Score 0.01056
Published At July 30, 2025, 12:55 p.m.
Date Actor Action Source VulnerableCode Version
2025-07-31T08:09:39.000015+00:00 Mozilla Importer Import https://github.com/mozilla/foundation-security-advisories/blob/master/announce/2020/mfsa2020-54.yml 37.0.0