9.8

CVE-2021-4127: mozilla firefox_esr

CVSS: 9.8v3.1CriticalModified
AliasesDEBIAN-CVE-2021-4127
Published 22-12-2022Last modified 16-04-2025
Open JSON

Vulnerability summary

CVE-2021-4127 is a critical (CVSS 9.8) vulnerability in mozilla firefox_esr. EPSS estimates a 0.91% chance of exploitation in the next 30 days, higher than 59.3% of scored vulnerabilities. 1 public exploit is recorded.

Overall risk
70/100
0100
High · default modelHow is this calculated?
CVSS score
9.8/10
010
Critical · v3.1 (CVE.org)
EPSS score
0.91%
0%100%
Low · +0.01 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits1reference

Advisory lineage

Upstream 0 · Downstream 12
DSA-4874-1DSA-4876-1MGASA-2021-0163MGASA-2021-0164RHSA-2021:0989RHSA-2021:0990

Timeline

  1. 22-12-2022
    PublishedVulnerability first disclosed.
  2. 16-04-2025
    Last modifiedVulnerability information updated.

Description

An out of date graphics library (Angle) likely contained vulnerabilities that could potentially be exploited. This vulnerability affects Thunderbird < 78.9 and Firefox ESR < 78.9.

CVSS metrics

3 scores · 3 sources · 1 version

EPSS trend

Probability

0.91%

Chance of exploitation in the next 30 days

Percentile

59%

Versus all other CVEs

30-day change

+0.01 pp

From 0.90% on 19-09-2026

19-09-202619-10-2026
EPSS score
0.91%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

1 found
  • referenceUnverified

    Exploit Reference (bugzilla.mozilla.org)

    Maturity: unknown

Weaknesses

CWE · root cause

No weakness data has been published for this record.

Affected systems

Debian2 products
  • firefox-esr< 78.9.0esr-1
  • thunderbird< 1:78.9.0-1
Mozilla2 products

2 vendors · 4 products

References

4 links