Firefox 159 · Version Status
Firefox 159 End of Life Date
Firefox 159 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.
⚡
Firefox 159 reaches end of life on November 10, 2026. Plan your migration now — 14 days remaining.
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EOL Date
Nov 10, 2026
14 days remaining
Latest Release
159.0
Standard release
Release Date
Oct 27, 2026
Firefox 159 series
Where these dates come from
End of lifeNov 10, 2026endoflife.date (open dataset) · endoflife.datemedium · 1 source agrees ReleaseOct 27, 2026endoflife.date (open dataset) · endoflife.datemedium · 1 source agrees 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 159 was released on October 27, 2026 and support is scheduled to end on November 10, 2026 — a planned supported lifespan of 14 days, shorter than the 28 days median for Firefox releases. It is not an LTS release; Firefox reserves longer patch windows for its LTS versions. Its most recent patch is 159.0, published October 27, 2026.
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 159 end of life mean?
When Firefox 159 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 159 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 159 reach end of life?
Firefox 159 reaches end of life on November 10, 2026. That is 14 days remaining.
Is Firefox 159 still supported?
Firefox 159 is still supported but approaching end of life on November 10, 2026. Begin planning your migration now.
What should I upgrade to from Firefox 159?
The recommended upgrade from Firefox 159 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 159 past EOL?
When Firefox 159 reaches end of life, the maintainers stop issuing 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.