Vulnerability · Published Dec 8, 2021 · Assigned by mozilla
CVE-2021-43540
Medium 6.5
In plain English
A medium-severity security flaw in Firefox from Mozilla. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.9% (higher than 60% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS NVD)6.5Medium
Exploit odds (30 days)0.9%top 40.5% of all CVEs
Exploited in the wildNo reportsnot in CISA KEV
Attack toolingNoneno public tooling known
Official description
WebExtensions with the correct permissions were able to create and install ServiceWorkers for third-party websites that would not have been uninstalled with the extension. This vulnerability affects Firefox < 95.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.20 | firefox | 95.0-r0 | ALPINE-CVE-2021-43540 |
| Alpine:v3.21 | firefox | 95.0-r0 | ALPINE-CVE-2021-43540 |
| Alpine:v3.22 | firefox | 95.0-r0 | ALPINE-CVE-2021-43540 |
| Alpine:v3.23 | firefox | 95.0-r0 | ALPINE-CVE-2021-43540 |
| Alpine:v3.21 | librewolf | 95.0-r0 | ALPINE-CVE-2021-43540 |
| Alpine:v3.22 | librewolf | 95.0-r0 | ALPINE-CVE-2021-43540 |
| Alpine:v3.23 | librewolf | 95.0-r0 | ALPINE-CVE-2021-43540 |
| Alpine:v3.24 | librewolf | 95.0-r0 | ALPINE-CVE-2021-43540 |
| Ubuntu:22.04:LTS | firefox | 95.0+build1-0ubuntu1 | UBUNTU-CVE-2021-43540 |
Affected products (as reported)
References
- https://www.mozilla.org/security/advisories/mfsa2021-52/ x_refsource_MISC
- https://bugzilla.mozilla.org/show_bug.cgi?id=1636629 x_refsource_MISC
- GLSA-202202-03 vendor-advisory, x_refsource_GENTOO