- Description
- Elysia is a Typescript framework for request validation, type inference, OpenAPI documentation and client-server communication. Versions 1.4.0 through 1.4.16 contain a prototype pollution vulnerability in `mergeDeep` after merging results of two standard schema validations with the same key. Due to the ordering of merging, there must be an any type that is set as a standalone guard, to allow for the `__proto__ prop` to be merged. When combined with GHSA-8vch-m3f4-q8jf this allows for a full RCE by an attacker. This issue is fixed in version 1.4.17. To workaround, remove the `__proto__ key` from body.
- Source
- security-advisories@github.com
- NVD status
- Analyzed
- Products
- elysia
CVSS 4.0
- Type
- Secondary
- Base score
- 9.1
- Impact score
- -
- Exploitability score
- -
- Vector string
- CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
- Severity
- CRITICAL
CVSS 3.1
- Type
- Primary
- Base score
- 9.8
- Impact score
- 5.9
- Exploitability score
- 3.9
- Vector string
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- Severity
- CRITICAL
- security-advisories@github.com
- CWE-1321
- Hype score
- Not currently trending
Elysia affected by Prototype Pollution (CVE-2025-66456). Updating to a patched version is recommended to mitigate potential security risks. https://t.co/GiotLqIP8M
@pulsepatchio
11 Dec 2025
0 Impressions
0 Retweets
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0 Replies
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CVE-2025-66456 Elysia is a Typescript framework for request validation, type inference, OpenAPI documentation and client-server communication. Versions 1.4.0 through 1.4.16 contain … https://t.co/z2yJde4wPk
@CVEnew
10 Dec 2025
137 Impressions
0 Retweets
0 Likes
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0 Replies
0 Quotes
CVE-2025-66456 | Critical 9.1/10 Prototype Pollution affecting routes with Standard Schema with multiple Standalone Schemas We highly recommend updating Elysia to 1.4.17 or higher immediately https://t.co/ZohocHIcW7
@saltyAom
9 Dec 2025
27799 Impressions
19 Retweets
359 Likes
57 Bookmarks
12 Replies
5 Quotes
[
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:a:elysiajs:elysia:*:*:*:*:*:node.js:*:*",
"matchCriteriaId": "41035CD2-DE13-469A-984F-6BC1CCCF2695",
"versionEndExcluding": "1.4.17",
"versionStartIncluding": "1.4.0",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
]