5.4

CVE-2026-12330: mozilla firefox

CVSS: 5.4v3.1MediumAnalyzed
AliasesUBUNTU-CVE-2026-12330DEBIAN-CVE-2026-12330CGA-48rj-c23v-f3p6
Published 16-06-2026Last modified 16-06-2026
Open JSON

Vulnerability summary

CVE-2026-12330 is a medium (CVSS 5.4) vulnerability in mozilla firefox. EPSS estimates a 0.16% chance of exploitation in the next 30 days, higher than 5.3% of scored vulnerabilities.

Overall risk
22/100
0100
Low · default modelHow is this calculated?
CVSS score
5.4/10
010
Medium · v3.1 (CVE.org)
EPSS score
0.16%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 36 · Related 13
MGASA-2026-0242MGASA-2026-0243MGASA-2026-0326OPENSUSE-SU-2026:11055-1OPENSUSE-SU-2026:11072-1OPENSUSE-SU-2026:21043-1

Timeline

  1. 16-06-2026
    PublishedVulnerability first disclosed.
  2. 16-06-2026
    Last modifiedVulnerability information updated.

Description

Incorrect boundary conditions in the Internationalization component. This vulnerability was fixed in Firefox ESR 140.12, Firefox ESR 115.37, and Thunderbird 140.12.

CVSS metrics

4 scores · 4 sources · 1 version

EPSS trend

Probability

0.16%

Chance of exploitation in the next 30 days

Percentile

5%

Versus all other CVEs

30-day change

0.00 pp

From 0.16% on 19-09-2026

19-09-202619-10-2026
EPSS score
0.16%

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

Chainguard2 products
  • firefox< 140.12.0-r0
  • firefox-esr< 140.12.0-r0
Debian2 products
  • firefox-esr< 140.12.0esr-1~deb12u1 | < 140.12.0esr-1~deb13u1 | < 140.12.0esr-1
  • thunderbird< 1:140.12.0esr-1~deb12u1 | < 1:140.12.0esr-1~deb13u1 | < 1:140.12.0esr-1
Mozilla2 products
Ubuntu1 product
  • thunderbirdAll versions (No fix recorded)
Wolfi1 product
  • firefox< 140.12.0-r0

5 vendors · 8 products

References

9 links