{"id":"DEBIAN-CVE-2026-19566","details":"Net::CIDR::Set versions before 0.23 for Perl allow memory exhaustion and malformed set ranges via unbounded IPv6 prefix lengths.  The _encode method accepts any prefix length matching `(0|[1-9][0-9]*)` and passes it to _width2bits(), which builds the mask as `'1' x ($width + 8)`, one character per bit. The _inc() method then unpacks the packed mask into a Perl array of one scalar per byte, so the prefix length alone sets the allocation size: `::/100000000` builds a 100 MB string and a 12.5 million element array. The value being tested is parsed, not just the configured ranges: contains() builds a set from its argument, and _guess_coder() tries the IPv4 coder and then the IPv6 coder, so an IPv4-only set expands an oversized IPv6 prefix length before the mixed address width check rejects it.  Any caller that passes untrusted input to contains() or add() can exhaust process memory. A prefix length above 128 is also stored as a range that does not match the requested block: 2001:db8::/129 stringifies back unchanged, contains() of its own base address returns false, and removing it from a set drops the base address while the set still prints as covering it.","modified":"2026-10-01T03:02:57.265102875Z","published":"2026-08-12T09:17:29.753Z","upstream":["CVE-2026-19566"],"references":[{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2026-19566"}],"affected":[{"package":{"name":"libnet-cidr-set-perl","ecosystem":"Debian:12","purl":"pkg:deb/debian/libnet-cidr-set-perl?arch=source&distro=bookworm"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.13-4","0.13-5","0.15-1","0.19-1","0.20-1","0.21-1","0.22-1","0.23-1"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-19566.json"}},{"package":{"name":"libnet-cidr-set-perl","ecosystem":"Debian:13","purl":"pkg:deb/debian/libnet-cidr-set-perl?arch=source&distro=trixie"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.15-1","0.15-1+deb13u1","0.19-1","0.20-1","0.21-1","0.22-1","0.23-1"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-19566.json"}},{"package":{"name":"libnet-cidr-set-perl","ecosystem":"Debian:14","purl":"pkg:deb/debian/libnet-cidr-set-perl?arch=source&distro=forky"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.23-1"}]}],"versions":["0.15-1","0.19-1","0.20-1","0.21-1","0.22-1"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-19566.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"}]}