UBUNTU-CVE-2026-64194

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Source
https://ubuntu.com/security/CVE-2026-64194
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-64194.json
JSON Data
https://api.osv.dev/v1/vulns/UBUNTU-CVE-2026-64194
Upstream
  • CVE-2026-64194
Published
2026-07-20T19:17:00Z
Modified
2026-07-29T10:18:53Z
Severity
  • 7.5 (High) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H CVSS Calculator
  • Ubuntu - medium
Summary
[none]
Details

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.

References

Affected packages

Ubuntu:14.04:LTS
libnet-dns-perl

Package

Name
libnet-dns-perl
Purl
pkg:deb/ubuntu/libnet-dns-perl?arch=source&distro=trusty

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected

Affected versions

0.*
0.68-1.2
0.68-1.2build1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "libnet-dns-perl",
            "binary_version": "0.68-1.2build1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-64194.json"
Ubuntu:16.04:LTS
libnet-dns-perl

Package

Name
libnet-dns-perl
Purl
pkg:deb/ubuntu/libnet-dns-perl?arch=source&distro=xenial

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected

Affected versions

0.*
0.81-2
0.81-2build1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "libnet-dns-perl",
            "binary_version": "0.81-2build1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-64194.json"
Ubuntu:18.04:LTS
libnet-dns-perl

Package

Name
libnet-dns-perl
Purl
pkg:deb/ubuntu/libnet-dns-perl?arch=source&distro=bionic

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected

Affected versions

1.*
1.10-2

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "libnet-dns-perl",
            "binary_version": "1.10-2"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-64194.json"
Ubuntu:20.04:LTS
libnet-dns-perl

Package

Name
libnet-dns-perl
Purl
pkg:deb/ubuntu/libnet-dns-perl?arch=source&distro=focal

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected

Affected versions

1.*
1.20-1
1.21-1
1.22-1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "libnet-dns-perl",
            "binary_version": "1.22-1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-64194.json"
Ubuntu:22.04:LTS
libnet-dns-perl

Package

Name
libnet-dns-perl
Purl
pkg:deb/ubuntu/libnet-dns-perl?arch=source&distro=jammy

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected

Affected versions

1.*
1.29-1
1.32-1
1.33-1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "libnet-dns-perl",
            "binary_version": "1.33-1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-64194.json"
Ubuntu:24.04:LTS
libnet-dns-perl

Package

Name
libnet-dns-perl
Purl
pkg:deb/ubuntu/libnet-dns-perl?arch=source&distro=noble

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected

Affected versions

1.*
1.39-2ubuntu1
1.40-1ubuntu1
1.44-1ubuntu1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "libnet-dns-perl",
            "binary_version": "1.44-1ubuntu1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-64194.json"
Ubuntu:26.04:LTS
libnet-dns-perl

Package

Name
libnet-dns-perl
Purl
pkg:deb/ubuntu/libnet-dns-perl?arch=source&distro=resolute

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected

Affected versions

1.*
1.50-1ubuntu1
1.53-1ubuntu1
1.54-1ubuntu1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "libnet-dns-perl",
            "binary_version": "1.54-1ubuntu1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-64194.json"