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Fencer Vulns
medium 6.5

CVE-2025-6431 json

The prompt in Firefox for Android that asks before opening a link in an external application could be bypassed

published 2025-06-24 16 mo ago modified 2026-09-30 39 d ago also EUVD-2025-19087

cvss
6.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 16%
public exploits
0
none known

Summary

When a link can be opened in an external application, Firefox for Android will, by default, prompt the user before doing so. An attacker could have bypassed this prompt, potentially exposing the user to security vulnerabilities or privacy leaks in external applications. *This bug only affects Firefox for Android. Other versions of Firefox are unaffected.*. This vulnerability was fixed in Firefox 140.

Patch / fix

  • mozilla firefox 140
  • MozillaFirefox-branding-SLE SLES for SAP 15 SP5, SLES for SAP 15 SP4, SLES for SAP 15 SP3 +12 more 140-150200.9.21.1
  • pipewire SLE Module for Package Hub 15 SP7, SLE Module for Package Hub 15 SP6 0.3.6-150200.3.11.1
  • pipewire SLES for SAP 15 SP3, SLES 15 SP3-LTSS, SLE High Performance Computing 15 SP3-LTSS +1 more 0.3.24-150300.4.8.1
  • pipewire SLES for SAP 15 SP4, SLES 15 SP4-LTSS, SLE High Performance Computing 15 SP4-LTSS +1 more 0.3.49-150400.3.7.1
  • pipewire SLES for SAP 15 SP5, SLES 15 SP5-LTSS, SLE High Performance Computing 15 SP5-LTSS +1 more 0.3.64-150500.3.7.2
  • MozillaFirefox SLES for SAP 15 SP5, SLES for SAP 15 SP4, SLES for SAP 15 SP3 +12 more 140.1.0-150200.152.193.1
  • xdg-desktop-portal SLES for SAP 15 SP3, SLES 15 SP3-LTSS, SLE High Performance Computing 15 SP3-LTSS +1 more 1.8.0-150200.5.8.1
  • xdg-desktop-portal SLES for SAP 15 SP4, SLES 15 SP4-LTSS, SLE High Performance Computing 15 SP4-LTSS +1 more 1.10.1-150400.3.8.1

suse advisories SUSE-SU-2025:02529-1SUSE-SU-2025:02339-1

  • firefox-esr openSUSE Tumbleweed 140.1.0-1.1
  • MozillaFirefox openSUSE Tumbleweed 140.0.2-1.1

opensuse advisories openSUSE-SU-2025:15371-1openSUSE-SU-2025:15325-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2025-6431 updated cvss 3.4

firefox: The prompt in Firefox for Android that asks before opening a link in an external application could be bypassed

  • Red Hat Enterprise Linux 6 firefox Red Hat Enterprise Linux 7 firefox Red Hat Enterprise Linux 8 firefox Red Hat Enterprise Linux 9 firefox, firefox-x11 Red Hat Enterprise Linux 10 firefox, firefox-flatpak
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
16 mo ago

Exploit prediction

0.25% chance of exploitation in the next 30 days, higher than 16% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CISA ADP 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
CNA 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N

Affected products

  • Mozilla Firefox

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.