Firefox 143 · Version Status
Firefox 143 End of Life Date
Firefox 143 end-of-life date, support status, and CVE risk. Data reconciled from official vendor documentation and endoflife.date at every build; the source of each date is on the product page.
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Firefox 143 is past end of life. This version no longer receives security patches. 389 days past EOL — migrate to a supported version immediately.
EOL Date
Oct 14, 2025
389 days past EOL
Latest Release
143.0.4
Standard release
Release Date
Sep 16, 2025
Firefox 143 series
Where these dates come from
End of lifeOct 14, 2025Vendor's own page, read by our adapter · product-details.mozilla.org · checked Nov 4, 2026high · 2 sources agree Confidence: high = two or more independent sources agree (the vendor's page read by our adapter, a person's check against the vendor, the dataset the date came from); medium = one; low = the vendor page disagrees or our last read is stale.
How we source dates.
Lifecycle detail
Firefox 143 was released on September 16, 2025 and support ended on October 14, 2025 — a supported lifespan of 28 days, in line with the 28 days median for Firefox releases. It was not an LTS release; Firefox reserves longer patch windows for its LTS releases. Its latest release on record is 143.0.4, published October 3, 2025 — 11 days before support ended. It has been past its end-of-life date for 1 year and 1 month. 15 newer Firefox releases have shipped since.
Attack Surface
10/30 Medium tier
CISA KEV Exposure
20/20 Named in CISA KEV
Extended Support
10/10 None available
EOL Risk Score™ — proprietary methodology by endoflife.ai. Factors: EOL recency, attack surface breadth, CISA KEV catalog presence, extended support availability. Updated at every build.
Methodology → ·
View score card →
| Version | Latest | EOL Date | Status |
|---|
| 78 LTS |
78.15.0 |
Nov 2, 2021 |
EOL |
| 91 LTS |
91.13.0 |
Sep 20, 2022 |
EOL |
| 102 LTS |
102.15.1 |
Sep 26, 2023 |
EOL |
| 103 |
103.0.2 |
Aug 23, 2022 |
EOL |
| 104 |
104.0.2 |
Sep 20, 2022 |
EOL |
| 105 |
105.0.3 |
Oct 18, 2022 |
EOL |
| 106 |
106.0.5 |
Nov 15, 2022 |
EOL |
| 107 |
107.0.1 |
Dec 13, 2022 |
EOL |
What does Firefox 143 end of life mean?
When Firefox 143 reaches end of life, the maintainers stop issuing security patches for this version. CVEs discovered after the EOL date are publicly disclosed on the National Vulnerability Database with no patch available. Exploit code frequently appears on GitHub within days of disclosure.
The CVE blind spot: A CVE-based scan does not show the ongoing accumulation of unpatched vulnerabilities in EOL software versions. Some scanners flag unsupported versions of common products, but coverage varies, and none of them give you the date in advance. Running Firefox 143 past its EOL date creates a growing attack surface that a clean scan result does not rule out.
Migrate to Firefox 153 or implement compensating controls — network segmentation, enhanced monitoring, restricted access — while migration is underway.
Frequently Asked Questions
When does Firefox 143 reach end of life?
Firefox 143 reached end of life on October 14, 2025. This version is no longer receiving security patches.
Is Firefox 143 still supported?
No. Firefox 143 reached end of life on October 14, 2025 and is no longer receiving security patches.
What should I upgrade to from Firefox 143?
The recommended upgrade from Firefox 143 is
Firefox 153 — the latest actively supported version. Check the
Firefox full timeline for all supported versions.
What are the security risks of running Firefox 143 past EOL?
Since Firefox 143 reached end of life, the maintainers no longer issue security patches. Any CVEs disclosed after the EOL date accumulate with no vendor fix. A CVE-based scan does not show this — it is the CVE blind spot; some scanners flag unsupported versions of common products, but coverage varies and none give the date in advance. Organizations running EOL Firefox should migrate immediately or implement compensating controls.