CVE-2021-29993

HIGHNVD 8.18.1—

8.1

Firefox for Android allowed navigations through the intent:// protocol, which could be used to cause crashes and UI spoofs. *This bug only affects Firefox for Android. Other operating systems are unaffected.*. This vulnerability affects Firefox < 92.

CVSS v3: 8.1
EG Score: 8.1(medium)
EPSS: 52.8%
KEV: Not listed

Published

November 3, 2021

Last Modified

November 21, 2024

References (4)

security@mozillahttps://bugzilla.mozilla.org/buglist.cgi?bug_id=1712242%2C1708767%2C1712240%2C1708544%2C1729259
security@mozillahttps://www.mozilla.org/security/advisories/mfsa2021-38/
af854a3a-2127-422b-91ae-364da2661108https://bugzilla.mozilla.org/buglist.cgi?bug_id=1712242%2C1708767%2C1712240%2C1708544%2C1729259
af854a3a-2127-422b-91ae-364da2661108https://www.mozilla.org/security/advisories/mfsa2021-38/

Data Freshness Timeline

(refreshed 12× in last 7d / 20× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

2026-06-08 14:15 UTCEPSS rescore
2026-06-07 15:23 UTCEPSS rescore
2026-06-07 15:23 UTCEPSS rescore
2026-06-06 13:46 UTCEPSS rescore
2026-06-06 13:46 UTCEPSS rescore
2026-06-06 13:46 UTCEPSS rescore
2026-06-05 22:45 UTCEPSS rescore
2026-06-05 22:45 UTCEPSS rescore
2026-06-05 06:09 UTCEPSS rescore
2026-06-05 06:09 UTCEPSS rescore
2026-06-04 13:10 UTCEPSS rescore
2026-06-04 13:10 UTCEPSS rescore
2026-06-02 20:11 UTCEPSS rescore
2026-06-02 20:11 UTCEPSS rescore
2026-06-02 20:11 UTCEPSS rescore
2026-06-01 13:50 UTCEPSS rescore
2026-06-01 13:50 UTCEPSS rescore
2026-05-31 22:29 UTCEPSS rescore
2026-05-31 22:29 UTCEPSS rescore
2026-05-31 00:15 UTCEPSS rescore

Frequently asked(5)

What is CVE-2021-29993?

CVE-2021-29993 is a high vulnerability published on November 3, 2021. Firefox for Android allowed navigations through the intent:// protocol, which could be used to cause crashes and UI spoofs. This bug only affects Firefox for Android. Other operating systems are unaffected.. This vulnerability affects Firefox < 92.

When was CVE-2021-29993 disclosed?

CVE-2021-29993 was first published in the National Vulnerability Database on November 3, 2021, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.

Is CVE-2021-29993 actively exploited?

CVE-2021-29993 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 52.8% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.

What is the CVSS score of CVE-2021-29993?

CVE-2021-29993 has a CVSS v3 base score of 8.1 (NVD).

How do I remediate CVE-2021-29993?

Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-29993, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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CVE-2021-29993

📅 Published

🔄 Last Modified

🔗 References (4)