TI-2021-03084 Aliases CVE-2021-4221 GHSA-wmph-fgw4-55rj

If a domain name contained a RTL character, it would cause the domain to be rendered to…

MEDIUM 53CWE-1007Published 2022-12-22 · Updated 2025-04-16

Key facts

Attack vector: Network
Privileges required: None
User interaction: Required
Attack complexity: Low
Impact type: —
Confidentiality · integrity · availability: None · Low · None
Fix status: Fixed

Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA.

Summary

If a domain name contained a RTL character, it would cause the domain to be rendered to the right of the path. This could lead to user confusion and spoofing attacks. <br>*This bug only affects Firefox for Android. Other operating systems are unaffected.*<br>*Note*: Due to a clerical error this advisory was not included in the original announcement, and was added in Feburary 2022. This vulnerability affects Firefox < 92.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV

EPSS 0.0043 37th percentileScored 2026-11-07

Public exploit Yes 1 exploit referenceTagged by NVD

Fix Fixed Firefox (Mozilla): 92

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: Poc
Automatable: No
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
Mozilla	Firefox	before 92	92	Patch available	CNA

Firefox VendorMozilla Affected before 92 Fixed in 92 Patch available CNA

CPE configurations NVD · 2

CPE	Versions	Role	Vendor
cpe:2.3:a:mozilla:firefox::::::::	before 92.0	Vulnerable	Mozilla
cpe:2.3:o:google:android:-:::::::*	not specified by NVD	Running on	Google

cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:* Versions before 92.0 Vulnerable ·Mozilla
cpe:2.3:o:google:android:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Google

Remediation

Fix · CNA Firefox (Mozilla) Fixed in 92

Timeline

2026-10-02 Threatist record created from CVE-2021-4221
2026-10-03 Alias added: GHSA-wmph-fgw4-55rj

References

Exploit 1

https://bugzilla.mozilla.org/show_bug.cgi?id=1704422

Advisory 1

https://www.mozilla.org/security/advisories/mfsa2021-38/

TI-2024-08981 Use after free in Mozilla Firefox KEVCVSS 3.1CRITICAL 9.8
TI-2022-09832 Use after free in Mozilla Firefox KEVCVSS 3.1CRITICAL 9.6
TI-2019-08769 Improper input validation in Mozilla Firefox ESR KEVCVSS 3.1CRITICAL 10.0
TI-2010-03577 Mozilla Firefox 3.5.x through 3.5.14 and 3.6.x through 3.6.11, Thunderbird 3.1.6 before… KEVCVSS 3.1CRITICAL 9.8
TI-2023-04799 Out-of-bounds write in Google Chrome KEVCVSS 3.1HIGH 8.8
TI-2023-04477 Out-of-bounds write in Google Chrome KEVCVSS 3.1HIGH 8.8

See all 3444 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences