4.3

CVE-2021-38509: debian debian_linux

CVSS: 4.3v3.1MediumModified
AliasesUBUNTU-CVE-2021-38509DEBIAN-CVE-2021-38509
Published 08-12-2021Last modified 04-08-2024

Vulnerability summary

CVE-2021-38509 is a medium (CVSS 4.3) vulnerability in debian debian_linux. EPSS estimates a 1.76% chance of exploitation in the next 30 days, higher than 77.6% of scored vulnerabilities.

Overall risk
18/100
0100
Low · default modelHow is this calculated?
CVSS score
4.3/10
010
Medium · v3.1 (NVD)
EPSS score
1.76%
0%100%
Low · +0.12 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 26 · Related 12

Timeline

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

Description

Due to an unusual sequence of attacker-controlled events, a Javascript alert() dialog with arbitrary (although unstyled) contents could be displayed over top an uncontrolled webpage of the attacker's choosing. This vulnerability affects Firefox < 94, Thunderbird < 91.3, and Firefox ESR < 91.3.

CVSS metrics

4 scores · 3 sources · 2 versions

EPSS trend

Probability

1.76%

Chance of exploitation in the next 30 days

Percentile

78%

Versus all other CVEs

30-day change

+0.12 pp

From 1.64% on 19-09-2026

19-09-202619-10-2026
EPSS score
1.76%

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

Affected systems

Ubuntu6 products
  • firefox< 94.0+build3-0ubuntu0.18.04.1 | < 94.0+build3-0ubuntu0.20.04.1 | < 94.0+build3-0ubuntu1
  • mozjs38All versions (No fix recorded)
  • mozjs52All versions (No fix recorded)
  • mozjs68All versions (No fix recorded)
  • mozjs78All versions (No fix recorded)
Debian3 products
  • firefox-esr< 91.3.0esr-1
  • thunderbird< 1:91.3.0-1
  • debian_linuxEOL9.0 | 10.0 | 11.0
Mozilla3 products

3 vendors · 12 products

References

18 links
Show all 18 references