CVE-2026-84504

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Source
https://cve.org/CVERecord?id=CVE-2026-84504
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-84504.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-84504
Aliases
  • GHSA-667r-xxjv-c9mm
Published
2026-09-04T09:40:18Z
Modified
2026-09-10T03:30:33Z
Severity
  • 8.1 (High) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N CVSS Calculator
Summary
fastify vulnerable to request body replacement via an async validation result collision
Details

fastify versions before 5.12.2 treat the object resolved by a successful Ajv async validator as the value result protocol used by custom validator compilers. If a request that passes its route schema contains a property named value at the root, fastify replaces the entire request body with that property's value before the handler runs, so the handler receives a different object than the one that satisfied the schema. An authenticated low-privilege caller can use this to make nested data replace the validated body and trigger an operation the route schema did not authorize, leading to unauthorized state changes and data disclosure. Users should upgrade to fastify 5.12.2 or later.

Database specific 
{
    "cna_assigner": "openjs",
    "cwe_ids": [
        "CWE-20"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/84xxx/CVE-2026-84504.json"
}
References

Affected packages

Git / github.com/fastify/fastify

Affected ranges

Type
GIT
Repo
https://github.com/fastify/fastify
Events
Introduced
0 Unknown introduced commit / All previous commits are affected
Fixed
942a2be8704244db778f8db9a0bb4951b8825156
Database specific
Show details 
{
    "extracted_events": [
        {
            "introduced": "0"
        },
        {
            "fixed": "5.12.2"
        }
    ],
    "source": [
        "AFFECTED_FIELD",
        "DESCRIPTION"
    ]
}

Affected versions

v0.*
v0.1.0
v0.10.0
v0.11.0
v0.11.1
v0.12.0
v0.13.0
v0.13.1
v0.14.0
v0.14.1
v0.15.0
v0.15.1
v0.15.2
v0.15.3
v0.16.0
v0.17.0
v0.18.0
v0.19.0
v0.19.1
v0.2.0
v0.20.0
v0.20.1
v0.21.0
v0.22.0
v0.23.0
v0.24.0
v0.25.0
v0.25.1
v0.25.2
v0.25.3
v0.26.0
v0.26.1
v0.26.2
v0.27.0
v0.28.0
v0.28.1
v0.28.2
v0.29.0
v0.29.1
v0.29.2
v0.3.0
v0.30.0
v0.30.1
v0.30.2
v0.30.3
v0.31.0
v0.32.0
v0.33.0
v0.34.0
v0.35.0
v0.35.1
v0.35.2
v0.35.3
v0.35.4
v0.35.5
v0.35.6
v0.35.7
v0.36.0
v0.37.0
v0.38.0
v0.39.0
v0.39.1
v0.4.0
v0.40.0
v0.41.0
v0.42.0
v0.43.0
v0.5.0
v0.6.0
v0.7.0
v0.7.1
v0.8.0
v0.9.0
v1.*
v1.0.0
v1.0.0-rc.1
v1.0.0-rc.2
v1.0.0-rc.3
v1.1.0
v1.1.1
v1.10.0
v1.11.0
v1.11.1
v1.11.2
v1.12.0
v1.12.1
v1.13.0
v1.2.0
v1.2.1
v1.3.0
v1.3.1
v1.4.0
v1.5.0
v1.6.0
v1.7.0
v1.8.0
v1.9.0
v2.*
v2.0.0
v2.0.0-rc.0
v2.0.0-rc.1
v2.0.0-rc.2
v2.0.0-rc.3
v2.0.0-rc.4
v2.0.0-rc.5
v2.0.0-rc.6
v2.0.1
v2.1.0
v2.14.0
v2.15.1
v2.2.0
v2.3.0
v3.*
v3.0.0
v3.0.0-alpha.1
v3.0.0-rc.1
v3.0.0-rc.2
v3.0.0-rc.3
v3.0.0-rc.4
v3.0.0-rc.5
v3.0.1
v3.0.2
v3.0.3
v3.1.0
v3.1.1
v3.10.0
v3.10.1
v3.11.0
v3.12.0
v3.13.0
v3.14.0
v3.14.1
v3.14.2
v3.15.0
v3.15.1
v3.16.0
v3.16.1
v3.16.2
v3.17.0
v3.18.0
v3.18.1
v3.19.0
v3.19.1
v3.19.2
v3.2.0
v3.2.1
v3.20.0
v3.20.1
v3.20.2
v3.21.0
v3.21.1
v3.21.2
v3.21.3
v3.21.4
v3.21.5
v3.21.6
v3.22.0
v3.22.1
v3.23.0
v3.23.1
v3.24.0
v3.24.1
v3.25.0
v3.25.1
v3.25.2
v3.25.3
v3.26.0
v3.27.0
v3.27.1
v3.27.2
v3.3.0
v3.4.0
v3.4.1
v3.5.0
v3.5.1
v3.6.0
v3.7.0
v3.8.0
v3.9.0
v3.9.1
v3.9.2
v4.*
v4.0.0
v4.0.0-alpha.1
v4.0.0-alpha.2
v4.0.0-alpha.3
v4.0.0-rc.1
v4.0.0-rc.2
v4.0.0-rc.3
v4.0.0-rc.4
v4.0.0-rc.5
v4.0.1
v4.0.2
v4.0.3
v4.1.0
v4.2.0
v4.2.1
v4.3.0
v4.4.0
v4.5.0
v4.5.1
v4.5.2
v5.*
v5.0.0
v5.0.0-alpha.1
v5.0.0-alpha.2
v5.0.0-alpha.4
v5.1.0
v5.10.0
v5.11.0
v5.11.1
v5.11.2
v5.11.3
v5.12.0
v5.12.1
v5.2.0
v5.2.1
v5.2.2
v5.3.0
v5.3.1
v5.3.2
v5.3.3
v5.4.0
v5.5.0
v5.6.0
v5.6.1
v5.6.2
v5.7.0
v5.7.1
v5.7.2
v5.7.3
v5.7.4
v5.8.0
v5.8.1
v5.8.2
v5.8.3
v5.8.4
v5.8.5
v5.9.0

Database specific

source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-84504.json"