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puma — security advisory

Type: advisorySources: OSVAdvisory ID: DEBIAN-CVE-2026-47736

Puma is a Ruby/Rack web server built for parallelism. From 5.5.0 until 7.2.1 and 8.0.2, when PROXY protocol v1 support is enabled, Puma reads incoming bytes into an internal buffer while waiting for CRLF to determine whether a PROXY v1 line is present, allowing an attacker that continuously sends bytes without CRLF to cause unbounded in-process memory growth and additional CPU cost from repeatedly scanning the growing buffer. This issue is fixed in versions 7.2.1 and 8.0.2.

Products
puma
Affected versions
5.6.5-3, 5.6.5-3+deb12u1, 6.6.0-4, 8.0.2-1, 8.0.2-2, 8.0.2-3
Fixed versions
5.6.5-3+deb12u2, 8.0.2-1
CVEs
CVE-2026-47736
Confirmed fixed CVEs
Not specified
Updated in this feed
28 Oct 2026, 04:01 UTC · Revision 1

Source evidence

DEBIAN-CVE-2026-47736

core-osv · Original source

Published 14 Jul 2026, 20:17 UTC

Puma is a Ruby/Rack web server built for parallelism. From 5.5.0 until 7.2.1 and 8.0.2, when PROXY protocol v1 support is enabled, Puma reads incoming bytes into an internal buffer while waiting for CRLF to determine whether a PROXY v1 line is present, allowing an attacker that continuously sends bytes without CRLF to cause unbounded in-process memory growth and additional CPU cost from repeatedly scanning the growing buffer. This issue is fixed in versions 7.2.1 and 8.0.2.

osv:DEBIAN-CVE-2026-47736

puma

Fixed versions: 5.6.5-3+deb12u2

puma

Fixed versions: Not specified

puma

Fixed versions: 8.0.2-1

Complete source record
{
  "id": "108fec908f2d53863b906c46766e538b095e82458779d9ceda7494e6bac1ce6b",
  "url": "https://osv.dev/vulnerability/DEBIAN-CVE-2026-47736",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "DEBIAN-CVE-2026-47736",
    "summary": "Puma is a Ruby/Rack web server built for parallelism. From 5.5.0 until 7.2.1 and 8.0.2, when PROXY protocol v1 support is enabled, Puma reads incoming bytes into an internal buffer while waiting for CRLF to determine whether a PROXY v1 line is present, allowing an attacker that continuously sends bytes without CRLF to cause unbounded in-process memory growth and additional CPU cost from repeatedly scanning the growing buffer. This issue is fixed in versions 7.2.1 and 8.0.2.",
    "evidence": "osv:DEBIAN-CVE-2026-47736",
    "products": [
      {
        "name": {
          "value": "puma",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "5.6.5-3+deb12u2",
            "evidence": "/affected/0/ranges"
          }
        ],
        "affected_versions": [
          {
            "value": "5.6.5-3",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "5.6.5-3+deb12u1",
            "evidence": "/affected/0/versions"
          }
        ]
      },
      {
        "name": {
          "value": "puma",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "6.6.0-4",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "8.0.2-1",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "8.0.2-2",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "8.0.2-3",
            "evidence": "/affected/1/versions"
          }
        ]
      },
      {
        "name": {
          "value": "puma",
          "evidence": "/affected/2/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "8.0.2-1",
            "evidence": "/affected/2/ranges"
          }
        ],
        "affected_versions": [
          {
            "value": "6.6.0-4",
            "evidence": "/affected/2/versions"
          }
        ]
      }
    ],
    "severity": "high",
    "structured": {
      "id": "DEBIAN-CVE-2026-47736",
      "aliases": [
        "DEBIAN-CVE-2026-47736"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "5.6.5-3+deb12u2"
                }
              ]
            }
          ],
          "package": {
            "name": "puma",
            "purl": "pkg:deb/debian/puma?arch=source&distro=bookworm",
            "ecosystem": "Debian:12"
          },
          "versions": [
            "5.6.5-3",
            "5.6.5-3+deb12u1"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-47736.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                }
              ]
            }
          ],
          "package": {
            "name": "puma",
            "purl": "pkg:deb/debian/puma?arch=source&distro=trixie",
            "ecosystem": "Debian:13"
          },
          "versions": [
            "6.6.0-4",
            "8.0.2-1",
            "8.0.2-2",
            "8.0.2-3"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-47736.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "8.0.2-1"
                }
              ]
            }
          ],
          "package": {
            "name": "puma",
            "purl": "pkg:deb/debian/puma?arch=source&distro=forky",
            "ecosystem": "Debian:14"
          },
          "versions": [
            "6.6.0-4"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-47736.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        }
      ],
      "modified": "2026-10-07T12:00:07.658866648Z",
      "provider": "osv",
      "upstream": [
        "CVE-2026-47736"
      ],
      "references": [
        "https://security-tracker.debian.org/tracker/CVE-2026-47736"
      ]
    },
    "related_cves": [
      {
        "value": "CVE-2026-47736",
        "evidence": "/upstream"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 95006,
  "published_at": "2026-07-14T20:17:03.62+00:00"
}