{"id":"UBUNTU-CVE-2026-49943","details":"CZ.NIC BIRD Internet Routing Daemon through 2.19.0 contains a stack-based buffer overflow in the BGP AS_PATH mask matching implementation in nest/a-path.c. The as_path_match() function uses a fixed-size stack array of 2048 + 1 pm_pos entries, while parse_path() expands AS_PATH segments from a received BGP UPDATE without enforcing a corresponding capacity limit. When RFC 8654 BGP Extended Messages are enabled and a BIRD filter evaluates an AS path mask expression such as \"bgp_path ~ [= ... =]\", an established BGP peer can send a long AS_PATH containing more than 2048 expanded ASNs. This causes parse_path()/as_path_match() to write beyond the fixed stack buffer, resulting in a crash of the daemon. NOTE: reportedly, the Supplier's position is that a fix is not being prioritized because all network operators should already be rejecting routes with unusually long attributes.","modified":"2026-06-12T09:04:21.384486242Z","published":"2026-06-02T17:16:00Z","upstream":["CVE-2026-49943"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-49943"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-49943"},{"type":"REPORT","url":"https://www.openwall.com/lists/oss-security/2026/06/02/2"}],"affected":[{"package":{"name":"bird","ecosystem":"Ubuntu:16.04:LTS","purl":"pkg:deb/ubuntu/bird?arch=source&distro=xenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.5.0-4","1.5.0-4build1"],"ecosystem_specific":{"binaries":[{"binary_version":"1.5.0-4build1","binary_name":"bird"},{"binary_name":"bird-bgp","binary_version":"1.5.0-4build1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-49943.json"}},{"package":{"name":"bird","ecosystem":"Ubuntu:18.04:LTS","purl":"pkg:deb/ubuntu/bird?arch=source&distro=bionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.6.3-3"],"ecosystem_specific":{"binaries":[{"binary_name":"bird","binary_version":"1.6.3-3"},{"binary_version":"1.6.3-3","binary_name":"bird-bgp"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-49943.json"}},{"package":{"name":"bird","ecosystem":"Ubuntu:20.04:LTS","purl":"pkg:deb/ubuntu/bird?arch=source&distro=focal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.6.7-1","1.6.8-1"],"ecosystem_specific":{"binaries":[{"binary_version":"1.6.8-1","binary_name":"bird"},{"binary_name":"bird-bgp","binary_version":"1.6.8-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-49943.json"}},{"package":{"name":"bird2","ecosystem":"Ubuntu:20.04:LTS","purl":"pkg:deb/ubuntu/bird2?arch=source&distro=focal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.0.5-1","2.0.7-2"],"ecosystem_specific":{"binaries":[{"binary_name":"bird2","binary_version":"2.0.7-2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-49943.json"}},{"package":{"name":"bird","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/bird?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.6.8-2.1"],"ecosystem_specific":{"binaries":[{"binary_version":"1.6.8-2.1","binary_name":"bird"},{"binary_version":"1.6.8-2.1","binary_name":"bird-bgp"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-49943.json"}},{"package":{"name":"bird2","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/bird2?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.0.7-4.1","2.0.8-2"],"ecosystem_specific":{"binaries":[{"binary_name":"bird2","binary_version":"2.0.8-2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-49943.json"}},{"package":{"name":"bird","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/bird?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.6.8-2.1","1.6.8-2.1build1","1.6.8-2.1build2"],"ecosystem_specific":{"binaries":[{"binary_name":"bird","binary_version":"1.6.8-2.1build2"},{"binary_version":"1.6.8-2.1build2","binary_name":"bird-bgp"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-49943.json"}},{"package":{"name":"bird2","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/bird2?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.0.12-7","2.14-1","2.14-1build1","2.14-1build2"],"ecosystem_specific":{"binaries":[{"binary_version":"2.14-1build2","binary_name":"bird2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-49943.json"}},{"package":{"name":"bird2","ecosystem":"Ubuntu:25.10","purl":"pkg:deb/ubuntu/bird2?arch=source&distro=questing"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.16.1-1","2.17-1","2.17.1-1"],"ecosystem_specific":{"binaries":[{"binary_version":"2.17.1-1","binary_name":"bird2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-49943.json"}},{"package":{"name":"bird3","ecosystem":"Ubuntu:25.10","purl":"pkg:deb/ubuntu/bird3?arch=source&distro=questing"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.1.0-1"],"ecosystem_specific":{"binaries":[{"binary_version":"3.1.0-1","binary_name":"bird3"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/m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