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MediumFix available

starlet — security advisory

Type: advisorySources: OSVAdvisory ID: DEBIAN-CVE-2026-40561

Starlet versions through 0.31 for Perl allows HTTP Request Smuggling via Improper Header Precedence. Starlet incorrectly prioritizes "Content-Length" over "Transfer-Encoding: chunked" when both headers are present in an HTTP request. Per RFC 7230 3.3.3, Transfer-Encoding must take precedence. An attacker could exploit this to smuggle malicious HTTP requests via a front-end reverse proxy.

Products
starlet
Affected versions
0.31-2, 0.31-3, 0.32-1
Fixed versions
0.31-2+deb13u1, 0.31-3
CVEs
CVE-2026-40561
Confirmed fixed CVEs
Not specified
Updated in this feed
1 Nov 2026, 17:46 UTC · Revision 2

Source evidence

DEBIAN-CVE-2026-40561

core-osv · Original source

Published 3 May 2026, 01:15 UTC

Starlet versions through 0.31 for Perl allows HTTP Request Smuggling via Improper Header Precedence. Starlet incorrectly prioritizes "Content-Length" over "Transfer-Encoding: chunked" when both headers are present in an HTTP request. Per RFC 7230 3.3.3, Transfer-Encoding must take precedence. An attacker could exploit this to smuggle malicious HTTP requests via a front-end reverse proxy.

osv:DEBIAN-CVE-2026-40561

starlet

Fixed versions: Not specified

starlet

Fixed versions: 0.31-2+deb13u1

starlet

Fixed versions: 0.31-3

Complete source record
{
  "id": "cdcf70591baefab36b4ffc52da796f2ff782c9b4c66af66be259e0903001bb0a",
  "url": "https://osv.dev/vulnerability/DEBIAN-CVE-2026-40561",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "DEBIAN-CVE-2026-40561",
    "summary": "Starlet versions through 0.31 for Perl allows HTTP Request Smuggling via Improper Header Precedence. Starlet incorrectly prioritizes \"Content-Length\" over \"Transfer-Encoding: chunked\" when both headers are present in an HTTP request. Per RFC 7230 3.3.3, Transfer-Encoding must take precedence. An attacker could exploit this to smuggle malicious HTTP requests via a front-end reverse proxy.",
    "evidence": "osv:DEBIAN-CVE-2026-40561",
    "products": [
      {
        "name": {
          "value": "starlet",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "0.31-2",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "0.31-3",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "0.32-1",
            "evidence": "/affected/0/versions"
          }
        ]
      },
      {
        "name": {
          "value": "starlet",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "0.31-2+deb13u1",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": [
          {
            "value": "0.31-2",
            "evidence": "/affected/1/versions"
          }
        ]
      },
      {
        "name": {
          "value": "starlet",
          "evidence": "/affected/2/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "0.31-3",
            "evidence": "/affected/2/ranges"
          }
        ],
        "affected_versions": [
          {
            "value": "0.31-2",
            "evidence": "/affected/2/versions"
          }
        ]
      }
    ],
    "severity": "medium",
    "structured": {
      "id": "DEBIAN-CVE-2026-40561",
      "aliases": [
        "DEBIAN-CVE-2026-40561"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                }
              ]
            }
          ],
          "package": {
            "name": "starlet",
            "purl": "pkg:deb/debian/starlet?arch=source&distro=bookworm",
            "ecosystem": "Debian:12"
          },
          "versions": [
            "0.31-2",
            "0.31-3",
            "0.32-1"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-40561.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "0.31-2+deb13u1"
                }
              ]
            }
          ],
          "package": {
            "name": "starlet",
            "purl": "pkg:deb/debian/starlet?arch=source&distro=trixie",
            "ecosystem": "Debian:13"
          },
          "versions": [
            "0.31-2"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-40561.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "0.31-3"
                }
              ]
            }
          ],
          "package": {
            "name": "starlet",
            "purl": "pkg:deb/debian/starlet?arch=source&distro=forky",
            "ecosystem": "Debian:14"
          },
          "versions": [
            "0.31-2"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-40561.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        }
      ],
      "modified": "2026-10-27T09:47:37.544523824Z",
      "provider": "osv",
      "upstream": [
        "CVE-2026-40561"
      ],
      "references": [
        "https://security-tracker.debian.org/tracker/CVE-2026-40561"
      ]
    },
    "related_cves": [
      {
        "value": "CVE-2026-40561",
        "evidence": "/upstream"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 461180,
  "published_at": "2026-05-03T01:15:58.39+00:00"
}