Puma is a Ruby/Rack web server built for parallelism. From 5.5.0 until 7.2.1 and 8.0.2, Puma is vulnerable to source IP spoofing when set_remote_address proxy_protocol: :v1 is enabled and persistent connections are used because Puma incorrectly re-parses PROXY protocol headers after each keep-alive request on the same connection, allowing an attacker to inject a second PROXY header and overwrite REMOTE_ADDR. This issue is fixed in versions 7.2.1 and 8.0.2.
{
"cna_assigner": "GitHub_M",
"cwe_ids": [
"CWE-290",
"CWE-345"
],
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/47xxx/CVE-2026-47737.json"
}{
"extracted_events": [
{
"range": [
{
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},
{
"fixed": "7.2.1"
}
],
"source": "AFFECTED_FIELD",
"strategy": "StringRangeExpression"
},
{
"range": [
{
"introduced": "8.0.0"
},
{
"fixed": "8.0.2"
}
],
"source": "AFFECTED_FIELD",
"strategy": "StringRangeExpression"
},
{
"range": [
{
"fixed": "439c6136d9c2275721b7864db3ee78af7c80889f"
}
],
"source": "REFERENCES_COMMIT"
},
{
"range": [
{
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}
],
"source": "REFERENCES_COMMIT"
},
{
"original_tag": "v7.2.1",
"range": [
{
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}
],
"source": "REFERENCES_TAG"
},
{
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"range": [
{
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],
"source": "REFERENCES_TAG"
}
]
}