{"id":"DEBIAN-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":"2026-09-14T17:03:17.973514600Z","published":"2026-06-02T17:16:37.657Z","upstream":["CVE-2026-49943"],"references":[{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2026-49943"}],"affected":[{"package":{"name":"bird","ecosystem":"Debian:12","purl":"pkg:deb/debian/bird?arch=source&distro=bookworm"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.6.8-2.1"],"ecosystem_specific":{"urgency":"unimportant"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-49943.json"}},{"package":{"name":"bird2","ecosystem":"Debian:12","purl":"pkg:deb/debian/bird2?arch=source&distro=bookworm"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"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"],"ecosystem_specific":{"urgency":"unimportant"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-49943.json"}},{"package":{"name":"bird2","ecosystem":"Debian:13","purl":"pkg:deb/debian/bird2?arch=source&distro=trixie"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"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"],"ecosystem_specific":{"urgency":"unimportant"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-49943.json"}},{"package":{"name":"bird2","ecosystem":"Debian:14","purl":"pkg:deb/debian/bird2?arch=source&distro=forky"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"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"],"ecosystem_specific":{"urgency":"unimportant"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-49943.json"}},{"package":{"name":"bird3","ecosystem":"Debian:13","purl":"pkg:deb/debian/bird3?arch=source&distro=trixie"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"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"],"ecosystem_specific":{"urgency":"unimportant"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-49943.json"}},{"package":{"name":"bird3","ecosystem":"Debian:14","purl":"pkg:deb/debian/bird3?arch=source&distro=forky"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"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"],"ecosystem_specific":{"urgency":"unimportant"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-49943.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:N/I:N/A:H"}]}