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bird2, bird3 — security advisory

Type: advisorySources: OSVAdvisory ID: DEBIAN-CVE-2026-112112

An IPv6 FlowSpec validation bypass in the CZ.NIC BIRD Internet Routing Daemon allows an established BGP peer to inject FlowSpec rules matching destinations outside the address space authorized by the unicast-route validation procedure. With validation enabled on the receiving flow6 channel, BIRD fails to reject a destination prefix component with a nonzero offset, contrary to RFC 8956 section 5. It validates a reconstructed prefix with zero-filled skipped bits, although the original FlowSpec component can match a broader set of IPv6 addresses. Given a suitable unicast route from the peer, the rule can pass validation and, where export policy permits, be propagated to downstream peers. Downstream enforcement may cause unauthorized traffic filtering or redirection.

Products
bird2, bird3
Affected versions
2.0.12-7, 2.14-1, 2.15-1, 2.15.1-1, 2.15.1-1.1, 2.16-1, 2.16.1-1, 2.17-1, 2.17.1-1, 2.17.1-1+deb13u1, 2.17.1-1+deb13u2, 2.17.2-1, 2.17.3-1, 2.17.3-2, 2.17.5-0+deb13u1, 2.18-1, 2.18.1-1, 2.19.0-1, 2.19.1-1, 2.19.2-1, 2.20.0-1, 3.1.0-1, 3.1.4-1, 3.1.5-1, 3.1.5-2, 3.1.7-0+deb13u1, 3.2.0-1, 3.2.1-1, 3.3.0-1, 3.3.0-1~bpo13+1, 3.3.1-1, 3.3.2-1, 3.3.2-1~bpo13+1, 3.4.0-1
Fixed versions
Not specified
CVEs
CVE-2026-112112
Confirmed fixed CVEs
Not specified
Updated in this feed
1 Nov 2026, 02:05 UTC · Revision 1

Source evidence

DEBIAN-CVE-2026-112112

core-osv · Original source

Published 18 Oct 2026, 23:16 UTC

An IPv6 FlowSpec validation bypass in the CZ.NIC BIRD Internet Routing Daemon allows an established BGP peer to inject FlowSpec rules matching destinations outside the address space authorized by the unicast-route validation procedure. With validation enabled on the receiving flow6 channel, BIRD fails to reject a destination prefix component with a nonzero offset, contrary to RFC 8956 section 5. It validates a reconstructed prefix with zero-filled skipped bits, although the original FlowSpec component can match a broader set of IPv6 addresses. Given a suitable unicast route from the peer, the rule can pass validation and, where export policy permits, be propagated to downstream peers. Downstream enforcement may cause unauthorized traffic filtering or redirection.

osv:DEBIAN-CVE-2026-112112

bird2

Fixed versions: Not specified

bird2

Fixed versions: Not specified

bird2

Fixed versions: Not specified

bird3

Fixed versions: Not specified

bird3

Fixed versions: Not specified

Complete source record
{
  "id": "42f05c29c74c4a498385b8d050a1a7303248ce0dfff692eb65f0b69e4bb5d019",
  "url": "https://osv.dev/vulnerability/DEBIAN-CVE-2026-112112",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "DEBIAN-CVE-2026-112112",
    "summary": "An IPv6 FlowSpec validation bypass in the CZ.NIC BIRD Internet Routing Daemon allows an established BGP peer to inject FlowSpec rules matching destinations outside the address space authorized by the unicast-route validation procedure. With validation enabled on the receiving flow6 channel, BIRD fails to reject a destination prefix component with a nonzero offset, contrary to RFC 8956 section 5. It validates a reconstructed prefix with zero-filled skipped bits, although the original FlowSpec component can match a broader set of IPv6 addresses. Given a suitable unicast route from the peer, the rule can pass validation and, where export policy permits, be propagated to downstream peers. Downstream enforcement may cause unauthorized traffic filtering or redirection.",
    "evidence": "osv:DEBIAN-CVE-2026-112112",
    "products": [
      {
        "name": {
          "value": "bird2",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "2.0.12-7",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "2.14-1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "2.15-1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "2.15.1-1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "2.15.1-1.1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "2.16-1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "2.16.1-1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "2.17-1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "2.17.1-1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "2.17.2-1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "2.17.3-1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "2.17.3-2",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "2.18-1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "2.18.1-1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "2.19.0-1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "2.19.1-1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "2.19.2-1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "2.20.0-1",
            "evidence": "/affected/0/versions"
          }
        ]
      },
      {
        "name": {
          "value": "bird2",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "2.17.1-1",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "2.17.1-1+deb13u1",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "2.17.1-1+deb13u2",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "2.17.2-1",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "2.17.3-1",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "2.17.3-2",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "2.17.5-0+deb13u1",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "2.18-1",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "2.18.1-1",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "2.19.0-1",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "2.19.1-1",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "2.19.2-1",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "2.20.0-1",
            "evidence": "/affected/1/versions"
          }
        ]
      },
      {
        "name": {
          "value": "bird2",
          "evidence": "/affected/2/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "2.17.1-1",
            "evidence": "/affected/2/versions"
          },
          {
            "value": "2.17.2-1",
            "evidence": "/affected/2/versions"
          },
          {
            "value": "2.17.3-1",
            "evidence": "/affected/2/versions"
          },
          {
            "value": "2.17.3-2",
            "evidence": "/affected/2/versions"
          },
          {
            "value": "2.18-1",
            "evidence": "/affected/2/versions"
          },
          {
            "value": "2.18.1-1",
            "evidence": "/affected/2/versions"
          },
          {
            "value": "2.19.0-1",
            "evidence": "/affected/2/versions"
          },
          {
            "value": "2.19.1-1",
            "evidence": "/affected/2/versions"
          },
          {
            "value": "2.19.2-1",
            "evidence": "/affected/2/versions"
          },
          {
            "value": "2.20.0-1",
            "evidence": "/affected/2/versions"
          }
        ]
      },
      {
        "name": {
          "value": "bird3",
          "evidence": "/affected/3/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "3.1.0-1",
            "evidence": "/affected/3/versions"
          },
          {
            "value": "3.1.4-1",
            "evidence": "/affected/3/versions"
          },
          {
            "value": "3.1.5-1",
            "evidence": "/affected/3/versions"
          },
          {
            "value": "3.1.5-2",
            "evidence": "/affected/3/versions"
          },
          {
            "value": "3.1.7-0+deb13u1",
            "evidence": "/affected/3/versions"
          },
          {
            "value": "3.2.0-1",
            "evidence": "/affected/3/versions"
          },
          {
            "value": "3.2.1-1",
            "evidence": "/affected/3/versions"
          },
          {
            "value": "3.3.0-1",
            "evidence": "/affected/3/versions"
          },
          {
            "value": "3.3.0-1~bpo13+1",
            "evidence": "/affected/3/versions"
          },
          {
            "value": "3.3.1-1",
            "evidence": "/affected/3/versions"
          },
          {
            "value": "3.3.2-1",
            "evidence": "/affected/3/versions"
          },
          {
            "value": "3.3.2-1~bpo13+1",
            "evidence": "/affected/3/versions"
          },
          {
            "value": "3.4.0-1",
            "evidence": "/affected/3/versions"
          }
        ]
      },
      {
        "name": {
          "value": "bird3",
          "evidence": "/affected/4/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "3.1.0-1",
            "evidence": "/affected/4/versions"
          },
          {
            "value": "3.1.4-1",
            "evidence": "/affected/4/versions"
          },
          {
            "value": "3.1.5-1",
            "evidence": "/affected/4/versions"
          },
          {
            "value": "3.1.5-2",
            "evidence": "/affected/4/versions"
          },
          {
            "value": "3.2.0-1",
            "evidence": "/affected/4/versions"
          },
          {
            "value": "3.2.1-1",
            "evidence": "/affected/4/versions"
          },
          {
            "value": "3.3.0-1",
            "evidence": "/affected/4/versions"
          },
          {
            "value": "3.3.0-1~bpo13+1",
            "evidence": "/affected/4/versions"
          },
          {
            "value": "3.3.1-1",
            "evidence": "/affected/4/versions"
          },
          {
            "value": "3.3.2-1",
            "evidence": "/affected/4/versions"
          },
          {
            "value": "3.3.2-1~bpo13+1",
            "evidence": "/affected/4/versions"
          },
          {
            "value": "3.4.0-1",
            "evidence": "/affected/4/versions"
          }
        ]
      }
    ],
    "severity": "low",
    "structured": {
      "id": "DEBIAN-CVE-2026-112112",
      "aliases": [
        "DEBIAN-CVE-2026-112112"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:L/VA:N/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": "bird2",
            "purl": "pkg:deb/debian/bird2?arch=source&distro=bookworm",
            "ecosystem": "Debian:12"
          },
          "versions": [
            "2.0.12-7",
            "2.14-1",
            "2.15-1",
            "2.15.1-1",
            "2.15.1-1.1",
            "2.16-1",
            "2.16.1-1",
            "2.17-1",
            "2.17.1-1",
            "2.17.2-1",
            "2.17.3-1",
            "2.17.3-2",
            "2.18-1",
            "2.18.1-1",
            "2.19.0-1",
            "2.19.1-1",
            "2.19.2-1",
            "2.20.0-1"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-112112.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                }
              ]
            }
          ],
          "package": {
            "name": "bird2",
            "purl": "pkg:deb/debian/bird2?arch=source&distro=trixie",
            "ecosystem": "Debian:13"
          },
          "versions": [
            "2.17.1-1",
            "2.17.1-1+deb13u1",
            "2.17.1-1+deb13u2",
            "2.17.2-1",
            "2.17.3-1",
            "2.17.3-2",
            "2.17.5-0+deb13u1",
            "2.18-1",
            "2.18.1-1",
            "2.19.0-1",
            "2.19.1-1",
            "2.19.2-1",
            "2.20.0-1"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-112112.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                }
              ]
            }
          ],
          "package": {
            "name": "bird2",
            "purl": "pkg:deb/debian/bird2?arch=source&distro=forky",
            "ecosystem": "Debian:14"
          },
          "versions": [
            "2.17.1-1",
            "2.17.2-1",
            "2.17.3-1",
            "2.17.3-2",
            "2.18-1",
            "2.18.1-1",
            "2.19.0-1",
            "2.19.1-1",
            "2.19.2-1",
            "2.20.0-1"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-112112.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                }
              ]
            }
          ],
          "package": {
            "name": "bird3",
            "purl": "pkg:deb/debian/bird3?arch=source&distro=trixie",
            "ecosystem": "Debian:13"
          },
          "versions": [
            "3.1.0-1",
            "3.1.4-1",
            "3.1.5-1",
            "3.1.5-2",
            "3.1.7-0+deb13u1",
            "3.2.0-1",
            "3.2.1-1",
            "3.3.0-1",
            "3.3.0-1~bpo13+1",
            "3.3.1-1",
            "3.3.2-1",
            "3.3.2-1~bpo13+1",
            "3.4.0-1"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-112112.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                }
              ]
            }
          ],
          "package": {
            "name": "bird3",
            "purl": "pkg:deb/debian/bird3?arch=source&distro=forky",
            "ecosystem": "Debian:14"
          },
          "versions": [
            "3.1.0-1",
            "3.1.4-1",
            "3.1.5-1",
            "3.1.5-2",
            "3.2.0-1",
            "3.2.1-1",
            "3.3.0-1",
            "3.3.0-1~bpo13+1",
            "3.3.1-1",
            "3.3.2-1",
            "3.3.2-1~bpo13+1",
            "3.4.0-1"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-112112.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        }
      ],
      "modified": "2026-10-23T18:05:33.649384129Z",
      "provider": "osv",
      "upstream": [
        "CVE-2026-112112"
      ],
      "references": [
        "https://security-tracker.debian.org/tracker/CVE-2026-112112"
      ]
    },
    "related_cves": [
      {
        "value": "CVE-2026-112112",
        "evidence": "/upstream"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 424508,
  "published_at": "2026-10-18T23:16:56.767+00:00"
}