6.5

CVE-2021-43540: mozilla firefox

CVSS: 6.5v3.1MediumModified
AliasesUBUNTU-CVE-2021-43540
Published 08-12-2021Last modified 04-08-2024
Open JSON

Vulnerability summary

CVE-2021-43540 is a medium (CVSS 6.5) vulnerability in mozilla firefox. EPSS estimates a 0.89% chance of exploitation in the next 30 days, higher than 58.7% of scored vulnerabilities.

Overall risk
26/100
0100
Medium · default modelHow is this calculated?
CVSS score
6.5/10
010
Medium · v3.1 (NVD)
EPSS score
0.89%
0%100%
Low · +0.03 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 3 · Related 3
OPENSUSE-SU-2024:11669-1OPENSUSE-SU-2024:14572-1USN-5186-1

Timeline

  1. 08-12-2021
    PublishedVulnerability first disclosed.
  2. 04-08-2024
    Last modifiedVulnerability information updated.

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.

CVSS metrics

3 scores · 2 sources · 2 versions

EPSS trend

Probability

0.89%

Chance of exploitation in the next 30 days

Percentile

59%

Versus all other CVEs

30-day change

+0.03 pp

From 0.86% on 20-09-2026

20-09-202620-10-2026
EPSS score
0.89%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

No weakness data has been published for this record.

Affected systems

Mozilla1 product
  • firefox≥ unspecified, < 95 | < 95.0
Ubuntu1 product
  • firefox< 95.0+build1-0ubuntu0.18.04.1 | < 95.0+build1-0ubuntu0.20.04.1 | < 95.0+build1-0ubuntu1

2 vendors · 2 products

References

7 links