protobufjs compiles protobuf definitions into JavaScript (JS) functions. From 8.2.0 until 8.6.5, the protobufjs Text Format extension parsed string-keyed map entries using ordinary property assignment, allowing a map entry with key proto to change the prototype of the returned map object instead of creating an own map entry in protobufjs/ext/textformat. This issue is fixed in version 8.6.5.
{
"cna_assigner": "GitHub_M",
"cwe_ids": [
"CWE-1321"
],
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/59xxx/CVE-2026-59876.json"
}{
"extracted_events": [
{
"cpe": "cpe:2.3:a:protobufjs_project:protobufjs:*:*:*:*:*:node.js:*:*",
"range": [
{
"introduced": "8.2.0"
},
{
"fixed": "8.6.5"
}
],
"source": "CPE_RANGE"
},
{
"range": [
{
"fixed": "9f97fe413072d3beb52c74e62d88ea8adc9444d8"
}
],
"source": "REFERENCES_COMMIT"
},
{
"original_tag": "protobufjs-v8.6.5",
"range": [
{
"fixed": "3f7b2fa2dd679f7099a30098a75bcd776615e86f"
}
],
"source": "REFERENCES_TAG"
}
]
}