erlang-cowlib — security advisory

{
  "id": "b90a7730417b940b2b7f6d6597a468ad8a535d2f1aef356202fd434ff48eb9d2",
  "url": "https://osv.dev/vulnerability/DEBIAN-CVE-2026-43970",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "DEBIAN-CVE-2026-43970",
    "summary": "Improper Handling of Highly Compressed Data (Data Amplification) vulnerability in ninenines cowlib allows unauthenticated remote denial of service via memory exhaustion. cow_spdy:inflate/2 in cowlib passes peer-supplied compressed bytes directly to zlib:inflate/2 with no output size bound. The SPDY header compression dictionary (?ZDICT) is public, and zlib compresses long runs of repeated bytes at roughly 1024:1, so a few kilobytes of SPDY frame payload can decompress to gigabytes on the BEAM heap, OOM-killing the node. A single unauthenticated SPDY frame is sufficient to trigger the condition. The parsers for syn_stream, syn_reply, and headers frame types are all affected via cow_spdy:parse_headers/2. This issue affects cowlib from 0.1.0 before 2.16.1.",
    "evidence": "osv:DEBIAN-CVE-2026-43970",
    "products": [
      {
        "name": {
          "value": "erlang-cowlib",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "1.3.0-3",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "2.17.1-1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "2.17.1-2",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "2.18.0-1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "2.19.0-1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "2.20.0-1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "2.21.0-1",
            "evidence": "/affected/0/versions"
          }
        ]
      },
      {
        "name": {
          "value": "erlang-cowlib",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "1.3.0-3",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "2.17.1-1",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "2.17.1-2",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "2.18.0-1",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "2.19.0-1",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "2.20.0-1",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "2.21.0-1",
            "evidence": "/affected/1/versions"
          }
        ]
      },
      {
        "name": {
          "value": "erlang-cowlib",
          "evidence": "/affected/2/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "2.17.1-1",
            "evidence": "/affected/2/ranges"
          }
        ],
        "affected_versions": [
          {
            "value": "1.3.0-3",
            "evidence": "/affected/2/versions"
          }
        ]
      }
    ],
    "severity": "high",
    "structured": {
      "id": "DEBIAN-CVE-2026-43970",
      "aliases": [
        "DEBIAN-CVE-2026-43970"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                }
              ]
            }
          ],
          "package": {
            "name": "erlang-cowlib",
            "purl": "pkg:deb/debian/erlang-cowlib?arch=source&distro=bookworm",
            "ecosystem": "Debian:12"
          },
          "versions": [
            "1.3.0-3",
            "2.17.1-1",
            "2.17.1-2",
            "2.18.0-1",
            "2.19.0-1",
            "2.20.0-1",
            "2.21.0-1"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-43970.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                }
              ]
            }
          ],
          "package": {
            "name": "erlang-cowlib",
            "purl": "pkg:deb/debian/erlang-cowlib?arch=source&distro=trixie",
            "ecosystem": "Debian:13"
          },
          "versions": [
            "1.3.0-3",
            "2.17.1-1",
            "2.17.1-2",
            "2.18.0-1",
            "2.19.0-1",
            "2.20.0-1",
            "2.21.0-1"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-43970.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "2.17.1-1"
                }
              ]
            }
          ],
          "package": {
            "name": "erlang-cowlib",
            "purl": "pkg:deb/debian/erlang-cowlib?arch=source&distro=forky",
            "ecosystem": "Debian:14"
          },
          "versions": [
            "1.3.0-3"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-43970.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        }
      ],
      "modified": "2026-10-27T10:01:40.726141003Z",
      "provider": "osv",
      "upstream": [
        "CVE-2026-43970"
      ],
      "references": [
        "https://security-tracker.debian.org/tracker/CVE-2026-43970"
      ]
    },
    "related_cves": [
      {
        "value": "CVE-2026-43970",
        "evidence": "/upstream"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 461352,
  "published_at": "2026-05-13T19:17:25.44+00:00"
}