High
puma — security advisory
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.
- Products
- puma
- Affected versions
- 3.12.0-2ubuntu1, 3.12.0-4ubuntu1, 3.12.4-1ubuntu2, 3.12.4-1ubuntu2+esm1, 3.12.4-1ubuntu2+esm2, 4.3.6-1ubuntu4, 5.5.2-2ubuntu2, 5.5.2-2ubuntu2+esm1, 5.5.2-2ubuntu2+esm2, 5.6.5-4ubuntu2, 5.6.5-4ubuntu3, 6.4.2-4ubuntu1, 6.4.2-4ubuntu3, 6.4.2-4ubuntu4, 6.4.2-4ubuntu4.3, 6.6.0-4, 6.6.0-4build1, 8.0.2-3build1
- Fixed versions
- Not specified
- CVEs
- CVE-2026-47737
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 03:06 UTC · Revision 1
Source evidence
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.
osv:UBUNTU-CVE-2026-47737
puma
Fixed versions: Not specified
puma
Fixed versions: Not specified
puma
Fixed versions: Not specified
puma
Fixed versions: Not specified
puma
Fixed versions: Not specified
Complete source record
{
"id": "afedfeee965929d4656591831925b38c738fb295b0cbf1e137184ba2d9f5d52c",
"url": "https://osv.dev/vulnerability/UBUNTU-CVE-2026-47737",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "UBUNTU-CVE-2026-47737",
"summary": "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.",
"evidence": "osv:UBUNTU-CVE-2026-47737",
"products": [
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"evidence": "/affected/0/versions"
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"evidence": "/affected/0/versions"
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{
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{
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{
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{
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{
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{
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],
"severity": "high",
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"aliases": [
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"metrics": [
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"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N"
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{
"type": "Ubuntu",
"score": "medium"
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"versions": [
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"database_specific": {
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],
"modified": "2026-10-17T13:00:20.462779701Z",
"provider": "osv",
"upstream": [
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],
"references": [
"https://ubuntu.com/security/CVE-2026-47737",
"https://www.cve.org/CVERecord?id=CVE-2026-47737",
"https://github.com/puma/puma/commit/439c6136d9c2275721b7864db3ee78af7c80889f",
"https://github.com/puma/puma/commit/ebe9db3929ab8299d19c8f5b41e8ef4f4b22fa58",
"https://github.com/puma/puma/pull/3944",
"https://github.com/puma/puma/pull/3947",
"https://github.com/puma/puma/releases/tag/v7.2.1",
"https://github.com/puma/puma/releases/tag/v8.0.2",
"https://github.com/puma/puma/security/advisories/GHSA-2vqw-3mp8-cgmx"
]
},
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],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 360430,
"published_at": "2026-07-14T20:17:00+00:00"
}