Elysia: Inefficient Algorithmic Complexity and Interpretation Conflict
Priority MEDIUM 40CWE-407Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-407.
Summary
Elysia is a Typescript framework for request validation, type inference, OpenAPI documentation, and client-server communication. Prior to 1.4.29, Elysia uses getAll in form data normalization for multipart/form-data endpoints, causing the amount of work to grow quadratically with the number of unique key-value pairs and allowing CPU exhaustion. This issue is fixed in version 1.4.29.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.0063 50th percentileScored 2026-11-07
Fix Fixed elysia (elysiajs): 1.4.29elysia (npm): 1.4.29
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| elysiajs | elysia | before 1.4.29 | 1.4.29 | Patch available | CNA |
| — | elysia (npm) | before 1.4.29 | 1.4.29 | Patch available | GHSA-9643-4qgh-g8mx |
- elysia Vendorelysiajs Affected before 1.4.29 Fixed in 1.4.29 Patch available CNA
- elysia (npm) Vendor— Affected before 1.4.29 Fixed in 1.4.29 Patch available GHSA-9643-4qgh-g8mx
Remediation
- Fix · CNA elysia (elysiajs) Fixed in 1.4.29
- Fix · GHSA-9643-4qgh-g8mx elysia (npm) Fixed in 1.4.29 Advisory →
Timeline
- 2026-10-02 Threatist record created from CVE-2026-56669
- 2026-10-03 Alias added: GHSA-9643-4qgh-g8mx
- 2026-10-28 EPSS moved to the 50th–90th percentile
References
Other 5
- https://github.com/elysiajs/elysia/security/advisories/GHSA-9643-4qgh-g8mx
- https://github.com/elysiajs/elysia/commit/8358ff9efbcedf9534995f5977f26b9ceab59329
- https://gist.github.com/jviide/ea040eabe7bac058326174e2cd42dfd9
- https://github.com/elysiajs/elysia/releases/tag/1.4.29
- https://github.com/elysiajs/elysia
More elysiajs vulnerabilities
- TI-2025-40888 Elysia vulnerable to prototype pollution with multiple standalone schema validation CVSS 4.0CRITICAL 9.1
- TI-2025-40889 Elysia affected by arbitrary code injection through cookie config CVSS 4.0HIGH 7.5
- TI-2026-23666 Elysia has a string URL format redos CVSS 3.1HIGH 7.5
- TI-2026-24417 Elysia Cookie Value Prototype Pollution CVSS 3.1MEDIUM 6.5
Sources
- CVE-2026-56669 · CVE Program
- CVE-2026-56669 · NVD
- FIRST EPSS
- GHSA-9643-4qgh-g8mx · GitHub Advisory Database · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences