libnet-cidr-set-perl — security advisory
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 ($width + 8)`, one character per bit. The _inc() method then unpacks the packed mask into a Perl array of one scalar per byte, so the prefix length alone sets the allocation size: `::/100000000` builds a 100 MB string and a 12.5 million element array. The value being tested is parsed, not just the configured ranges: contains() builds a set from its argument, and _guess_coder() tries the IPv4 coder and then the IPv6 coder, so an IPv4-only set expands an oversized IPv6 prefix length before the mixed address width check rejects it. Any caller that passes untrusted input to contains() or add() can exhaust process memory. A prefix length above 128 is also stored as a range that does not match the requested block: 2001:db8::/129 stringifies back unchanged, contains() of its own base address returns false, and removing it from a set drops the base address while the set still prints as covering it.
- Products
- libnet-cidr-set-perl
- Affected versions
- 0.13-4, 0.13-5, 0.15-1, 0.15-1+deb13u1, 0.19-1, 0.20-1, 0.21-1, 0.22-1, 0.23-1
- Fixed versions
- 0.23-1
- CVEs
- CVE-2026-19566
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 1 Nov 2026, 04:05 UTC · Revision 1
Source evidence
Net::CIDR::Set versions before 0.23 for Perl allow memory exhaustion and malformed set ranges via unbounded IPv6 prefix lengths. The _encode method accepts any prefix length matching `(0|[1-9][0-9]*)` and passes it to _width2bits(), which builds the mask as `'1' x ($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.
osv:DEBIAN-CVE-2026-19566
libnet-cidr-set-perl
Fixed versions: Not specified
libnet-cidr-set-perl
Fixed versions: Not specified
libnet-cidr-set-perl
Fixed versions: 0.23-1
Complete source record
{
"id": "caf9ebb9a99443540c8d8c0af86279275f5b8697197edb69dad199d7db1c799d",
"url": "https://osv.dev/vulnerability/DEBIAN-CVE-2026-19566",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "DEBIAN-CVE-2026-19566",
"summary": "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.",
"evidence": "osv:DEBIAN-CVE-2026-19566",
"products": [
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{
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{
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{
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{
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{
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{
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{
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"evidence": "/affected/1/versions"
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{
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"evidence": "/affected/1/versions"
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{
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{
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{
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{
"name": {
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"evidence": "/affected/2/ranges"
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"affected_versions": [
{
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"evidence": "/affected/2/versions"
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{
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{
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{
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],
"severity": "high",
"structured": {
"id": "DEBIAN-CVE-2026-19566",
"aliases": [
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],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
}
],
"affected": [
{
"ranges": [
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"events": [
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"package": {
"name": "libnet-cidr-set-perl",
"purl": "pkg:deb/debian/libnet-cidr-set-perl?arch=source&distro=bookworm",
"ecosystem": "Debian:12"
},
"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"
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"database_specific": {
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"ecosystem_specific": {
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{
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"package": {
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"purl": "pkg:deb/debian/libnet-cidr-set-perl?arch=source&distro=trixie",
"ecosystem": "Debian:13"
},
"versions": [
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"0.15-1+deb13u1",
"0.19-1",
"0.20-1",
"0.21-1",
"0.22-1",
"0.23-1"
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"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-19566.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
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},
{
"fixed": "0.23-1"
}
]
}
],
"package": {
"name": "libnet-cidr-set-perl",
"purl": "pkg:deb/debian/libnet-cidr-set-perl?arch=source&distro=forky",
"ecosystem": "Debian:14"
},
"versions": [
"0.15-1",
"0.19-1",
"0.20-1",
"0.21-1",
"0.22-1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-19566.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
}
],
"modified": "2026-10-24T09:47:28.438581068Z",
"provider": "osv",
"upstream": [
"CVE-2026-19566"
],
"references": [
"https://security-tracker.debian.org/tracker/CVE-2026-19566"
]
},
"related_cves": [
{
"value": "CVE-2026-19566",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 428971,
"published_at": "2026-08-12T09:17:29.753+00:00"
}