libslirp — security advisory

{
  "id": "fdac24598454b071915d1ee2aee213896a18ab22b24d67991f634a78ffefc1bf",
  "url": "https://osv.dev/vulnerability/DEBIAN-CVE-2026-9539",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "DEBIAN-CVE-2026-9539",
    "summary": "An out-of-bounds heap read and integer underflow in the TCP urgent data handling (sosendoob) in freedesktop.org libslirp version before v4.9.2 on hypervisor host environments (e.g., QEMU) allows a privileged guest VM attacker (root or CAP_NET_RAW) to leak gigabytes of sensitive host-process heap memory via sending crafted TCP segments with manipulated URG flags and urgent pointers (ti_urp).",
    "evidence": "osv:DEBIAN-CVE-2026-9539",
    "products": [
      {
        "name": {
          "value": "libslirp",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "4.7.0-1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "4.8.0-1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "4.9.1-1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "4.9.2-1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "4.9.3-1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "4.9.4-1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "4.9.5-1",
            "evidence": "/affected/0/versions"
          }
        ]
      },
      {
        "name": {
          "value": "libslirp",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "4.8.0-1+deb13u1",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": [
          {
            "value": "4.8.0-1",
            "evidence": "/affected/1/versions"
          }
        ]
      },
      {
        "name": {
          "value": "libslirp",
          "evidence": "/affected/2/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "4.9.2-1",
            "evidence": "/affected/2/ranges"
          }
        ],
        "affected_versions": [
          {
            "value": "4.8.0-1",
            "evidence": "/affected/2/versions"
          },
          {
            "value": "4.9.1-1",
            "evidence": "/affected/2/versions"
          }
        ]
      }
    ],
    "severity": "medium",
    "structured": {
      "id": "DEBIAN-CVE-2026-9539",
      "aliases": [
        "DEBIAN-CVE-2026-9539"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                }
              ]
            }
          ],
          "package": {
            "name": "libslirp",
            "purl": "pkg:deb/debian/libslirp?arch=source&distro=bookworm",
            "ecosystem": "Debian:12"
          },
          "versions": [
            "4.7.0-1",
            "4.8.0-1",
            "4.9.1-1",
            "4.9.2-1",
            "4.9.3-1",
            "4.9.4-1",
            "4.9.5-1"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-9539.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "4.8.0-1+deb13u1"
                }
              ]
            }
          ],
          "package": {
            "name": "libslirp",
            "purl": "pkg:deb/debian/libslirp?arch=source&distro=trixie",
            "ecosystem": "Debian:13"
          },
          "versions": [
            "4.8.0-1"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-9539.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "4.9.2-1"
                }
              ]
            }
          ],
          "package": {
            "name": "libslirp",
            "purl": "pkg:deb/debian/libslirp?arch=source&distro=forky",
            "ecosystem": "Debian:14"
          },
          "versions": [
            "4.8.0-1",
            "4.9.1-1"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-9539.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        }
      ],
      "modified": "2026-10-26T11:47:37.398293481Z",
      "provider": "osv",
      "upstream": [
        "CVE-2026-9539"
      ],
      "references": [
        "https://security-tracker.debian.org/tracker/CVE-2026-9539"
      ]
    },
    "related_cves": [
      {
        "value": "CVE-2026-9539",
        "evidence": "/upstream"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 450944,
  "published_at": "2026-06-24T05:17:31.1+00:00"
}