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Vulnerability details: VCID-w8xx-jpc7-77gh
Vulnerability ID VCID-w8xx-jpc7-77gh
Aliases CVE-2020-6806
Summary By carefully crafting promise resolutions, it was possible to cause an out-of-bounds read off the end of an array resized during script execution. This could have led to memory corruption and a potentially exploitable crash.
Status Published
Exploitability 0.5
Weighted Severity 9.0
Risk 4.5
Affected and Fixed Packages Package Details
Weaknesses (1)
CWE-125 Out-of-bounds Read
System Score Found at
cvssv3 8.8 https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2020-6806.json
epss 0.05209 https://api.first.org/data/v1/epss?cve=CVE-2020-6806
epss 0.05209 https://api.first.org/data/v1/epss?cve=CVE-2020-6806
epss 0.05209 https://api.first.org/data/v1/epss?cve=CVE-2020-6806
epss 0.05209 https://api.first.org/data/v1/epss?cve=CVE-2020-6806
epss 0.05209 https://api.first.org/data/v1/epss?cve=CVE-2020-6806
epss 0.05209 https://api.first.org/data/v1/epss?cve=CVE-2020-6806
epss 0.05209 https://api.first.org/data/v1/epss?cve=CVE-2020-6806
epss 0.05209 https://api.first.org/data/v1/epss?cve=CVE-2020-6806
epss 0.05209 https://api.first.org/data/v1/epss?cve=CVE-2020-6806
epss 0.05209 https://api.first.org/data/v1/epss?cve=CVE-2020-6806
epss 0.05209 https://api.first.org/data/v1/epss?cve=CVE-2020-6806
epss 0.05209 https://api.first.org/data/v1/epss?cve=CVE-2020-6806
epss 0.05209 https://api.first.org/data/v1/epss?cve=CVE-2020-6806
epss 0.05209 https://api.first.org/data/v1/epss?cve=CVE-2020-6806
epss 0.05209 https://api.first.org/data/v1/epss?cve=CVE-2020-6806
cvssv3.1 7.5 https://ftp.suse.com/pub/projects/security/yaml/suse-cvss-scores.yaml
cvssv2 6.8 https://nvd.nist.gov/vuln/detail/CVE-2020-6806
cvssv3.1 8.8 https://nvd.nist.gov/vuln/detail/CVE-2020-6806
archlinux Critical https://security.archlinux.org/AVG-1112
archlinux Critical https://security.archlinux.org/AVG-1115
generic_textual high https://www.mozilla.org/en-US/security/advisories/mfsa2020-08
generic_textual high https://www.mozilla.org/en-US/security/advisories/mfsa2020-09
generic_textual high https://www.mozilla.org/en-US/security/advisories/mfsa2020-10
Reference id Reference type URL
http://packetstormsecurity.com/files/157524/Firefox-js-ReadableStreamCloseInternal-Out-Of-Bounds-Access.html
https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2020-6806.json
https://api.first.org/data/v1/epss?cve=CVE-2020-6806
https://bugzilla.mozilla.org/show_bug.cgi?id=1612308
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-20503
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-6805
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-6806
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-6807
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-6811
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-6812
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-6814
https://ftp.suse.com/pub/projects/security/yaml/suse-cvss-scores.yaml
https://www.mozilla.org/security/advisories/mfsa2020-08/
https://www.mozilla.org/security/advisories/mfsa2020-09/
https://www.mozilla.org/security/advisories/mfsa2020-10/
1812200 https://bugzilla.redhat.com/show_bug.cgi?id=1812200
ASA-202003-11 https://security.archlinux.org/ASA-202003-11
ASA-202003-8 https://security.archlinux.org/ASA-202003-8
AVG-1112 https://security.archlinux.org/AVG-1112
AVG-1115 https://security.archlinux.org/AVG-1115
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:a:mozilla:firefox_esr:*:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:a:mozilla:firefox_esr:*:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:*
cpe:2.3:o:canonical:ubuntu_linux:16.04:*:*:*:esm:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:o:canonical:ubuntu_linux:16.04:*:*:*:esm:*:*:*
cpe:2.3:o:canonical:ubuntu_linux:18.04:*:*:*:lts:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:o:canonical:ubuntu_linux:18.04:*:*:*:lts:*:*:*
cpe:2.3:o:canonical:ubuntu_linux:19.10:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:o:canonical:ubuntu_linux:19.10:*:*:*:*:*:*:*
CVE-2020-6806 https://nvd.nist.gov/vuln/detail/CVE-2020-6806
mfsa2020-08 https://www.mozilla.org/en-US/security/advisories/mfsa2020-08
mfsa2020-09 https://www.mozilla.org/en-US/security/advisories/mfsa2020-09
mfsa2020-10 https://www.mozilla.org/en-US/security/advisories/mfsa2020-10
RHSA-2020:0905 https://access.redhat.com/errata/RHSA-2020:0905
RHSA-2020:0914 https://access.redhat.com/errata/RHSA-2020:0914
RHSA-2020:0918 https://access.redhat.com/errata/RHSA-2020:0918
RHSA-2020:0919 https://access.redhat.com/errata/RHSA-2020:0919
USN-4299-1 https://usn.ubuntu.com/4299-1/
USN-4328-1 https://usn.ubuntu.com/4328-1/
USN-4335-1 https://usn.ubuntu.com/4335-1/
No exploits are available.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H Found at https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2020-6806.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:H/PR:N/UI:R/S:U/C:H/I:H/A:H 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:P/I:P/A:P Found at https://nvd.nist.gov/vuln/detail/CVE-2020-6806
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:H/I:H/A:H Found at https://nvd.nist.gov/vuln/detail/CVE-2020-6806
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 0.89541
EPSS Score 0.05209
Published At July 30, 2025, 12:55 p.m.
Date Actor Action Source VulnerableCode Version
2025-07-31T08:09:40.445620+00:00 Mozilla Importer Import https://github.com/mozilla/foundation-security-advisories/blob/master/announce/2020/mfsa2020-09.yml 37.0.0