YUI End of Life (EOL) Dates & Support Timeline
Complete end-of-life dates, support windows, and security status for all YUI versions. Data sourced from endoflife.date and official vendor documentation. Updated at every deploy.
Running an EOL version? Get matched with support options — free ↓| Version | Latest Release | Release Date | EOL Date | Days | Status |
|---|---|---|---|---|---|
| 3 | 3.18.1 | Sep 29, 2009 | Aug 29, 2014 | 4376 days past EOL | EOL |
Live EOL badge for your README — updates automatically at every build.
[](https://endoflife.ai/yui)
YUI lifecycle status — the real story
YUI is the textbook case of an explicit corporate end of life: Yahoo announced the end of active YUI development on August 29, 2014, citing the rise of Node.js, package managers, and evolving JavaScript standards. The final release, 3.18.1, shipped in October 2014 — meaning every YUI deployment has now gone over a decade without patches.
YUI once ran substantial parts of the commercial web, and remnants survive in long-lived enterprise applications and CMS themes. Multiple publicly documented XSS vulnerabilities exist in YUI 2 and early YUI 3 components, and no fix will ever be issued.
Any live YUI dependency belongs at the top of a legacy remediation list — it is one of the few libraries where "unsupported" is not an inference but an eleven-year-old official announcement.
What does YUI end of life mean for your organization?
When a version of YUI reaches end of life, the maintainers stop issuing security patches. Vulnerabilities discovered after this date are publicly disclosed on the National Vulnerability Database, exploit code appears on GitHub, and your systems remain permanently exposed.
The CVE blind spot: Most vulnerability scanners check for known CVEs but do not flag the accumulation of unpatched vulnerabilities in EOL software. With a zero-day, nobody knows about the vulnerability. With EOL software, the vulnerability is public — listed, rated, and often weaponized — but no patch will ever exist. This is the most dangerous gap in enterprise security posture.
Organizations running EOL YUI should treat it as a vulnerability class in their risk register, apply compensating controls (network segmentation, enhanced monitoring, access restriction), and prioritize migration to a supported version.
Your options when YUI reaches end of life
There are four realistic paths. Which one is right depends far more on how long the system needs to keep running than on the version you are on today.
| Option | Best when | Watch out for |
|---|---|---|
| Move to a supported version | The system will outlive the current version's support window and you can schedule the work | Budget for compatibility testing, not just the upgrade itself — that is where the real cost sits |
| Replace the component | The project is unmaintained, or a better-supported alternative exists | The replacement has its own lifecycle and its own end-of-life date — you are changing vendors, not escaping the problem |
| Buy extended support | Migration is genuinely underway but cannot finish before the deadline, or the workload is frozen by certification or a third-party application | A bridge, not a destination — every year purchased is a year the migration still has to happen |
| Document accepted risk | The system is isolated, short-lived, or scheduled for retirement | Only defensible with real compensating controls and a written decision — auditors treat undocumented end-of-life software as a finding |
How to choose, in one question: how many more years does this system need to run? Under a year, extended support (where it exists) is usually cheaper than an emergency migration. One to three years, migrate — support purchased repeatedly costs more than doing the project once, and the project only gets harder as the version ages. Indefinitely, migrate now and plan the next migration before it surprises you.
Worth saying plainly, because vendors selling extended support rarely will: extended support is often the more expensive choice over a multi-year horizon. It is the right answer when a deadline is genuinely unreachable, not as a default. Compare the annual fee against the one-time cost of migrating before committing to either.
Formalizing decisions like this across your estate? Our free EOL policy template is a ready-to-adopt policy with risk tiers, remediation SLAs, and audit mapping — no signup, free to use and share.
Extended Support Options
If you cannot migrate immediately, extended support vendors provide continued security patches for EOL YUI versions. This is a bridge, not a permanent solution — plan your migration in parallel.
YUI has 1 version past end of life — security patches have stopped, but CVE disclosures haven't. Extended support past the official date exists for many products in this position — whether it exists for YUI is exactly what we check. Tell us where to reach you and we'll reply with matched options and pricing guidance — or an honest "no vendor covers this."