An established BGP peer must be able to send IPv6 FlowSpec to a receiving flow6 channel configured with \"validate yes\". A suitable unicast route from that peer must be present in the base table. Propagation additionally requires an export policy permitting the rule. Data-plane impact depends on downstream support for, acceptance of, and enforcement of the FlowSpec match and action.
"}],"value":"An established BGP peer must be able to send IPv6 FlowSpec to a receiving flow6 channel configured with \"validate yes\". A suitable unicast route from that peer must be present in the base table. Propagation additionally requires an export policy permitting the rule. Data-plane impact depends on downstream support for, acceptance of, and enforcement of the FlowSpec match and action."}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:a:nic:bird:*:*:*:*:*:*:*:*","versionEndIncluding":"2.20.0","versionStartIncluding":"2.0.9","vulnerable":true},{"criteria":"cpe:2.3:a:nic:bird:*:*:*:*:*:*:*:*","versionEndIncluding":"3.4.0","versionStartIncluding":"3.0.0","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"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."}],"metrics":[{"cvssV4_0":{"Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","Safety":"NOT_DEFINED","attackComplexity":"LOW","attackRequirements":"PRESENT","attackVector":"NETWORK","baseScore":2.3,"baseSeverity":"LOW","privilegesRequired":"LOW","providerUrgency":"NOT_DEFINED","subAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","userInteraction":"NONE","valueDensity":"NOT_DEFINED","vectorString":"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","version":"4.0","vulnAvailabilityImpact":"NONE","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"LOW","vulnerabilityResponseEffort":"NOT_DEFINED"},"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}]}],"problemTypes":[{"descriptions":[{"cweId":"CWE-1284","description":"CWE-1284 Improper Validation of Specified Quantity in Input","lang":"en","type":"CWE"}]}],"providerMetadata":{"dateUpdated":"2026-10-18T23:01:05.633Z","orgId":"8254265b-2729-46b6-b9e3-3dfca2d5bfca","shortName":"mitre"},"references":[{"tags":["patch"],"url":"https://gitlab.nic.cz/labs/bird/-/commit/7cf75587b6f38b87849fe192bf5dfd124b7702bc"},{"url":"https://www.rfc-editor.org/rfc/rfc8956.html#section-5"},{"url":"https://gitlab.nic.cz/labs/bird/-/blob/v2.20.0/nest/rt-table.c#L2686"},{"url":"https://gitlab.nic.cz/labs/bird/-/blob/v3.4.0/nest/rt-table.c#L4518"}],"solutions":[{"lang":"en","supportingMedia":[{"base64":false,"type":"text/html","value":"Apply upstream commit 7cf75587b6f38b87849fe192bf5dfd124b7702bc or a verified branch-specific backport. The fix requires the original IPv6 destination-prefix component to have offset zero before it can pass FlowSpec validation. The first fixed release has not yet been verified.
"}],"value":"Apply upstream commit 7cf75587b6f38b87849fe192bf5dfd124b7702bc or a verified branch-specific backport. The fix requires the original IPv6 destination-prefix component to have offset zero before it can pass FlowSpec validation. The first fixed release has not yet been verified."}],"x_generator":{"engine":"CVE-Request-form 0.0.1"}}},"cveMetadata":{"assignerOrgId":"8254265b-2729-46b6-b9e3-3dfca2d5bfca","assignerShortName":"mitre","cveId":"CVE-2026-112112","datePublished":"2026-10-18T23:01:05.633Z","dateReserved":"2026-10-18T23:01:05.103Z","dateUpdated":"2026-10-19T18:41:47.949Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-10-18 23:16:56","lastModifiedDate":"2026-10-19 21:14:14","problem_types":["CWE-1284","CWE-1284 CWE-1284 Improper Validation of Specified Quantity in Input"],"metrics":{"cvssMetricV40":[{"source":"cve@mitre.org","type":"Secondary","cvssData":{"version":"4.0","vectorString":"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","baseScore":2.3,"baseSeverity":"LOW","attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"PRESENT","privilegesRequired":"LOW","userInteraction":"NONE","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"LOW","vulnAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","exploitMaturity":"NOT_DEFINED","confidentialityRequirement":"NOT_DEFINED","integrityRequirement":"NOT_DEFINED","availabilityRequirement":"NOT_DEFINED","modifiedAttackVector":"NOT_DEFINED","modifiedAttackComplexity":"NOT_DEFINED","modifiedAttackRequirements":"NOT_DEFINED","modifiedPrivilegesRequired":"NOT_DEFINED","modifiedUserInteraction":"NOT_DEFINED","modifiedVulnConfidentialityImpact":"NOT_DEFINED","modifiedVulnIntegrityImpact":"NOT_DEFINED","modifiedVulnAvailabilityImpact":"NOT_DEFINED","modifiedSubConfidentialityImpact":"NOT_DEFINED","modifiedSubIntegrityImpact":"NOT_DEFINED","modifiedSubAvailabilityImpact":"NOT_DEFINED","Safety":"NOT_DEFINED","Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","valueDensity":"NOT_DEFINED","vulnerabilityResponseEffort":"NOT_DEFINED","providerUrgency":"NOT_DEFINED"}}],"ssvcV203":[{"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0","ssvcData":{"timestamp":"2026-10-19T18:39:04.870755Z","id":"CVE-2026-112112","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalImpact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"112112","Ordinal":"1","Title":"CVE-2026-112112","CVE":"CVE-2026-112112","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"112112","Ordinal":"1","NoteData":"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.","Type":"Description","Title":"CVE-2026-112112"}]}}}