# elysia (npm) vulnerabilities

5 known vulnerabilities (1 critical, 3 high, 1 medium), with the versions each affects and the releases that fix them.

## At a glance

- Latest release: 1.4.31 (Nov 5, 2026): no advisory affects it
- Newest unaffected release: 1.4.31 (Nov 5, 2026), the latest release
- Weekly downloads: 1.9M
- Dependents: 532
- Releases: 500+ since 1.0.0 (Mar 16, 2024)
- Registry: https://www.npmjs.com/package/elysia
- Releases read: Nov 8, 2026

## Version timeline

Affected versions per advisory, in version order:

- CVE-2026-56669: 1.0.0-beta.4 to 1.4.28 (1.4.29 is outside it)
- CVE-2026-31865: 1.0.0-beta.4 to 1.4.26 (1.4.27 is outside it)
- CVE-2026-30837: 1.0.0-beta.4 to 1.4.25 (1.4.26 is outside it)
- CVE-2025-66457: 1.0.0-beta.4 to 1.4.17 (1.4.18 is outside it)
- CVE-2025-66456: 1.4.0 to 1.4.17-exp.1 (1.4.17 is outside it)

Older releases aren't stored, so the earliest spans may start sooner.

## Advisories (5)

### [CVE-2026-56669](https://cve.now/CVE-2026-56669): Elysia: Inefficient Algorithmic Complexity and Interpretation Conflict

- Severity: High 7.5
- Published: Jul 8, 2026
- Affected: fixed in 1.4.29.
- Fixed in 1.4.29 (released Jun 16, 2026, 22 days before disclosure).
- The latest release, 1.4.31, is not affected.
- 19% of elysia downloads last week were affected versions (388.2K).

### [CVE-2026-31865](https://cve.now/CVE-2026-31865): Elysia Cookie Value Prototype Pollution

- Severity: Medium 6.5
- Published: Mar 18, 2026
- Affected: fixed in 1.4.27.
- Fixed in 1.4.27 (released Mar 1, 2026, 17 days before disclosure).
- The latest release, 1.4.31, is not affected.
- 11% of elysia downloads last week were affected versions (233.3K).

### [CVE-2026-30837](https://cve.now/CVE-2026-30837): Elysia has a string URL format redos

- Severity: High 7.5
- Published: Mar 10, 2026
- Affected: fixed in 1.4.26.
- Fixed in 1.4.26 (released Feb 25, 2026, 13 days before disclosure).
- The latest release, 1.4.31, is not affected.
- 11% of elysia downloads last week were affected versions (221.2K).

### [CVE-2025-66457](https://cve.now/CVE-2025-66457): Elysia affected by arbitrary code injection through cookie config

- Severity: High 7.5
- Published: Dec 9, 2025
- Affected: fixed in 1.4.18.
- Fixed in 1.4.18 (released Dec 4, 2025, 5 days before disclosure).
- The latest release, 1.4.31, is not affected.
- 7.2% of elysia downloads last week were affected versions (147.4K).

### [CVE-2025-66456](https://cve.now/CVE-2025-66456): Elysia vulnerable to prototype pollution with multiple standalone schema validation

- Severity: Critical 9.1
- Published: Dec 9, 2025
- Affected: from 1.4.0, fixed in 1.4.17.
- Fixed in 1.4.17 (released Dec 2, 2025, 7 days before disclosure).
- The latest release, 1.4.31, is not affected.
- 3.5% of elysia downloads last week were affected versions (72.6K).

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