4.3

CVE-2026-12303: mozilla firefox Out-of-bounds Read

CVSS: 4.3v3.1MediumAnalyzed
AliasesUBUNTU-CVE-2026-12303CGA-86g7-xfwj-v8rjCGA-xx2p-4h92-j8x2
Published 16-06-2026Last modified 16-06-2026
Open JSON

Vulnerability summary

CVE-2026-12303 is a medium (CVSS 4.3) Out-of-bounds Read vulnerability in mozilla firefox. EPSS estimates a 0.22% chance of exploitation in the next 30 days, higher than 12% of scored vulnerabilities.

Overall risk
17/100
0100
Low · default modelHow is this calculated?
CVSS score
4.3/10
010
Medium · v3.1 (CVE.org)
EPSS score
0.22%
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 2 · Related 3
OPENSUSE-SU-2026:11052-1OPENSUSE-SU-2026:11373-1CGA-F625-R4H9-HRR4

Timeline

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

Description

Information disclosure due to incorrect boundary conditions in the Graphics: WebGPU component. This vulnerability was fixed in Firefox 152 and Thunderbird 152.

CVSS metrics

3 scores · 3 sources · 1 version

EPSS trend

Probability

0.22%

Chance of exploitation in the next 30 days

Percentile

12%

Versus all other CVEs

30-day change

0.00 pp

From 0.22% on 21-09-2026

21-09-202621-10-2026
EPSS score
0.22%

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

Ubuntu8 products
  • mozjs102All versions (No fix recorded)
  • mozjs115All versions (No fix recorded)
  • mozjs38All versions (No fix recorded)
  • mozjs52All versions (No fix recorded)
  • mozjs68All versions (No fix recorded)
Mozilla2 products
Chainguard1 product
  • firefox< 152.0-r0
Wolfi1 product
  • firefox< 152.0-r0

4 vendors · 12 products

References

6 links