CVE-2026-56669: CWE-407: Inefficient Algorithmic Complexity in elysiajs elysia
Description
Elysia v1.4.28 is vulnerable to denial-of-service attacks due to CPU exhaustion in the form data normalization code. Elysia uses `getAll` to retrieve value from FormData. It is called directly relative to the total number of key-value pairs in the form data. The total amount of work the for loop has to do grows quadratically, so doubling the number of unique key-value pairs quadruples the amount of work. In the above PoC, each .getAll call scans through all of the `n` key-value pairs in the form data. Because there are `n` unique keys in the form data, there are .getAll calls, so in total the form data normalizer has to scan `n` x `n` key-value pairs. ### Impact Endpoints using `multipart/form-data` ### Patches 1.4.29 ### Workarounds no 100% confirm workaround beside updating the patch
CVSS v3.1
Score 7.5high
Affected software
elysiajs
elysia
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AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-56669 describes an inefficient algorithmic complexity vulnerability (CWE-407) in the elysiajs elysia framework prior to version 1.4.29. The vulnerability is due to the use of the getAll method during form data normalization for multipart/form-data endpoints, which causes the processing workload to increase quadratically relative to the number of unique key-value pairs. This inefficiency can be exploited to exhaust CPU resources, resulting in a denial of service condition. The vulnerability does not impact confidentiality or integrity but affects availability. The issue is resolved in version 1.4.29.
Potential Impact
The vulnerability allows an attacker to cause CPU exhaustion by sending multipart/form-data requests with many unique key-value pairs, leading to a denial of service. There is no impact on confidentiality or integrity. The CVSS v3.1 score is 7.5 (high), reflecting the network attack vector, low attack complexity, no privileges required, no user interaction, and impact limited to availability.
Mitigation Recommendations
Upgrade to elysia version 1.4.29 or later, where this inefficient algorithmic complexity issue has been fixed. Patch status is confirmed by the version-based fix. No other mitigation is indicated by the vendor advisory.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-06-22T16:39:01.043Z
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 6a4eb690c9d9e3dbe3b68743
Added to database: 07/08/2026, 20:44:00 UTC
Last enriched: 07/16/2026, 09:53:45 UTC
Last updated: 10/06/2026, 18:48:23 UTC
Views: 168
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