DEBIAN-CVE-2026-64194
Net::DNS versions through 1.55 for Perl allow Denial of Service via deep DNS compression pointer chains. Net::DNS::DomainName::decode follows RFC 1035 compression pointers by recursing into itself with no depth limit. It is possible to construct a name which saturates the call stack (at least with larger TCP responses), leading to a potential Denial of Service. The guard `$link < $offset` prevents forward and circular chains, but still allows arbitrarily long backward chains. The per-offset cache (`$cache`) is populated at the start of each call and short-circuits only re-traverses of the same offset - the initial descent through a fresh chain still recurses at full depth. A crafted packet can chain two-byte compression pointers so that each one points two bytes earlier than the previous, producing a chain length of `offset / 2`. For the 14-bit pointer field (max offset 16383) this gives up to ~8191 recursive frames. For a TCP DNS message the limit is the 16-bit length field (~32767 frames). Perl's default C stack handles only a few thousand frames; beyond that the process receives SIGSEGV or similar, which is a denial-of-service for any application parsing untrusted DNS data. The vulnerability is triggered by `Net::DNS::Packet->new(\$wire)` i.e. any point where the library decodes a DNS message from the network.
DEBIAN-CVE-2026-64194
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: osv:DEBIAN-CVE-2026-64194
libnet-dns-perl
Source reference: /affected/0/package/name
- Affected versions
- 1.36-1
Source reference:
/affected/0/versions - Fixed versions
- 1.36-1+deb12u1
Source reference:
/affected/0/ranges - Prerequisites
- Not stated in this record
libnet-dns-perl
Source reference: /affected/1/package/name
- Affected versions
- 1.50-1
Source reference:
/affected/1/versions1.53-1Source reference:
/affected/1/versions1.54-1Source reference:
/affected/1/versions1.55-1Source reference:
/affected/1/versions - Fixed versions
- 1.56-0+deb13u1
Source reference:
/affected/1/ranges - Prerequisites
- Not stated in this record
libnet-dns-perl
Source reference: /affected/2/package/name
- Affected versions
- 1.50-1
Source reference:
/affected/2/versions1.53-1Source reference:
/affected/2/versions1.54-1Source reference:
/affected/2/versions1.55-1Source reference:
/affected/2/versions - Fixed versions
- 1.56-1
Source reference:
/affected/2/ranges - Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "1.36-1+deb12u1"
}
]
}
],
"package": {
"name": "libnet-dns-perl",
"purl": "pkg:deb/debian/libnet-dns-perl?arch=source&distro=bookworm",
"ecosystem": "Debian:12"
},
"versions": [
"1.36-1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-64194.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "1.56-0+deb13u1"
}
]
}
],
"package": {
"name": "libnet-dns-perl",
"purl": "pkg:deb/debian/libnet-dns-perl?arch=source&distro=trixie",
"ecosystem": "Debian:13"
},
"versions": [
"1.50-1",
"1.53-1",
"1.54-1",
"1.55-1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-64194.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "1.56-1"
}
]
}
],
"package": {
"name": "libnet-dns-perl",
"purl": "pkg:deb/debian/libnet-dns-perl?arch=source&distro=forky",
"ecosystem": "Debian:14"
},
"versions": [
"1.50-1",
"1.53-1",
"1.54-1",
"1.55-1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-64194.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
}
]Publisher severity
No explicit severity was provided.
- Event
- #58132 · Revision 1
- Added to Heist Feed
- Publisher date