CVE-2020-15663
No exploitation reported by the sources we read.
- Published2020-10-01
- Fixed in80.0 · 78.2
- WeaknessCWE-427
Am I affected?
Debian, Ubuntu or Red Hat sometimes backport a fix without changing the upstream version number: such a version reads « to verify », never « affected ».With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.
Description
If Firefox is installed to a user-writable directory, the Mozilla Maintenance Service would execute updater.exe from the install location with system privileges. Although the Mozilla Maintenance Service does ensure that updater.exe is signed by Mozilla, the version could have been rolled back to a previous version which would have allowed exploitation of an older bug and arbitrary code execution with System Privileges. *Note: This issue only affected Windows operating systems. Other operating systems are unaffected.*. This vulnerability affects Firefox < 80, Thunderbird < 78.2, Thunderbird < 68.12, Firefox ESR < 68.12, and Firefox ESR < 78.2.
Timeline
dates in UTC- 2020-10-0119:15CVE publishedNVD
Observed activity
isMalicious corpus · updated 2026-10-23 18:48 UTCBlock these indicators
- Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2020-15663?format=txt
- CSV export: https://api.ismalicious.com/edl/cve/CVE-2020-15663?format=csv
- TAXII collection of exploited CVEs
- The EDL and CSV take an API key on the Pro plan.
Versions per branch
NVD| Branch | Affected | Fixed in | Source |
|---|---|---|---|
| 80.0 | < 80.0 | 80.0 | NVD |
| 78.x | ≥ 78.0, < 78.2 | 78.2 | NVD |
| Branch | Affected | Fixed in | Source |
|---|---|---|---|
| 78.x | ≥ 78.0, < 78.2 | 78.2 | NVD |
| 68.x | ≥ 68.0, < 68.12 | 68.12 | NVD |
| Branch | Affected | Fixed in | Source |
|---|---|---|---|
| 68.x | ≥ 68.0, < 68.12 | 68.12 | NVD |
as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.
Fix
- Update Mozilla firefox to 80.0 · 78.2
Advisories and patches
- bugzilla.mozilla.orgVendor Advisory
- www.mozilla.orgRelease Notes · Vendor Advisory
- www.mozilla.orgRelease Notes · Vendor Advisory
- www.mozilla.orgRelease Notes · Vendor Advisory
- www.mozilla.orgRelease Notes · Vendor Advisory
- www.mozilla.orgRelease Notes · Vendor Advisory
Detection
- Nuclei template
- none so far ProjectDiscovery
- Exploit-DB
- no entry Exploit-DB
- Proof-of-concept repositories
- none listed PoC-in-GitHub
Sources
- NVDCVSS 3.18.8read 2026-10-23
- NVDCVSS 2.09.3read 2026-10-23
- NVDweakness (CWE)CWE-427read 2026-10-23
- FIRST EPSSEPSS score2.7 %2026-10-22
Technical details
- CVSS v3 Vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
- Published
- 2020-10-01
- Last Modified
- 2026-06-17
- NVD status
- Modified
Frequently asked questions
What is CVE-2020-15663?
Is CVE-2020-15663 actively exploited?
What is the CVSS score for CVE-2020-15663?
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Surveillance reads the versions in your stack — a domain, a lockfile or a list — checks each CVE against the ranges its sources publish, and alerts you when one you run is exploited or enters CISA KEV. A version it cannot read stays « version not verified ».
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Same product first, then the same vendor advisory and the same publication week.