6.5

CVE-2026-53899: mozilla firefox_mobile

CVSS: 6.5v3.1MediumAnalyzed
AliasesCGA-8j9m-36xq-77p6CGA-cwc4-62wh-hm5v
Published 16-06-2026Last modified 16-06-2026
Open JSON

Vulnerability summary

CVE-2026-53899 is a medium (CVSS 6.5) vulnerability in mozilla firefox_mobile. EPSS estimates a 0.14% chance of exploitation in the next 30 days, higher than 2.7% of scored vulnerabilities.

Overall risk
26/100
0100
Medium · default modelHow is this calculated?
CVSS score
6.5/10
010
Medium · v3.1 (CVE.org)
EPSS score
0.14%
0%100%
Low · +0.04 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 0 · Related 1
CGA-4389-4MC9-3H2V

Timeline

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

Description

Firefox for iOS used partial domain matching when attaching cookies to PDF requests, allowing a malicious site on a suffix domain to receive cookies belonging to the target site. This vulnerability was fixed in Firefox for iOS 152.0.

CVSS metrics

4 scores · 4 sources · 1 version

EPSS trend

Probability

0.14%

Chance of exploitation in the next 30 days

Percentile

3%

Versus all other CVEs

30-day change

+0.04 pp

From 0.10% on 21-09-2026

21-09-202621-10-2026
EPSS score
0.14%

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

Chainguard1 product
  • firefox< 152.0-r0
Mozilla1 product
Wolfi1 product
  • firefox< 152.0-r0

3 vendors · 3 products

References

4 links