UBUNTU-CVE-2026-63091

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Source
https://ubuntu.com/security/CVE-2026-63091
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-63091.json
JSON Data
https://api.osv.dev/v1/vulns/UBUNTU-CVE-2026-63091
Upstream
Published
2026-07-20T15:16:00Z
Modified
2026-07-29T10:18:12Z
Severity
  • 6.5 (Medium) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N CVSS Calculator
  • 7.1 (High) CVSS_V4 - CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N CVSS Calculator
  • Ubuntu - medium
Summary
[none]
Details

ProFTPD before 1.3.9c and 1.3.10rc3 contains a signed integer overflow vulnerability in the mod_sftp module's SCP size-record parser that allows authenticated low-privilege attackers to bypass ASLR by sending a crafted file size value of UINT64_MAX, which results in a negative off_t value. Attackers can exploit the subsequent conversion to uint32_t, causing an approximately 4 GB requested read length and forcing the server to read beyond the end of the SSH channel data and write overread process memory into the uploaded file. In tested configurations, the disclosed data contains libc, libcrypto, and PIE pointers sufficient to derive their randomized base addresses, thereby bypassing ASLR and enabling reliable exploitation of memory corruption vulnerabilities in the same process.

References

Affected packages

Ubuntu:16.04:LTS
proftpd-dfsg

Package

Name
proftpd-dfsg
Purl
pkg:deb/ubuntu/proftpd-dfsg?arch=source&distro=xenial

Affected ranges

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

Affected versions

1.*
1.3.5-2
1.3.5a-1
1.3.5a-1build1
1.3.5a-1ubuntu0.1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "proftpd-basic",
            "binary_version": "1.3.5a-1ubuntu0.1"
        },
        {
            "binary_name": "proftpd-mod-geoip",
            "binary_version": "1.3.5a-1ubuntu0.1"
        },
        {
            "binary_name": "proftpd-mod-ldap",
            "binary_version": "1.3.5a-1ubuntu0.1"
        },
        {
            "binary_name": "proftpd-mod-mysql",
            "binary_version": "1.3.5a-1ubuntu0.1"
        },
        {
            "binary_name": "proftpd-mod-odbc",
            "binary_version": "1.3.5a-1ubuntu0.1"
        },
        {
            "binary_name": "proftpd-mod-pgsql",
            "binary_version": "1.3.5a-1ubuntu0.1"
        },
        {
            "binary_name": "proftpd-mod-sqlite",
            "binary_version": "1.3.5a-1ubuntu0.1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-63091.json"
Ubuntu:18.04:LTS
proftpd-dfsg

Package

Name
proftpd-dfsg
Purl
pkg:deb/ubuntu/proftpd-dfsg?arch=source&distro=bionic

Affected ranges

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

Affected versions

1.*
1.3.5d-1
1.3.5e-1build1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "proftpd-basic",
            "binary_version": "1.3.5e-1build1"
        },
        {
            "binary_name": "proftpd-mod-geoip",
            "binary_version": "1.3.5e-1build1"
        },
        {
            "binary_name": "proftpd-mod-ldap",
            "binary_version": "1.3.5e-1build1"
        },
        {
            "binary_name": "proftpd-mod-mysql",
            "binary_version": "1.3.5e-1build1"
        },
        {
            "binary_name": "proftpd-mod-odbc",
            "binary_version": "1.3.5e-1build1"
        },
        {
            "binary_name": "proftpd-mod-pgsql",
            "binary_version": "1.3.5e-1build1"
        },
        {
            "binary_name": "proftpd-mod-sqlite",
            "binary_version": "1.3.5e-1build1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-63091.json"
Ubuntu:20.04:LTS
proftpd-dfsg

Package

Name
proftpd-dfsg
Purl
pkg:deb/ubuntu/proftpd-dfsg?arch=source&distro=focal

Affected ranges

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

Affected versions

1.*
1.3.6-6build2
1.3.6c-1
1.3.6c-2
1.3.6c-2ubuntu0.1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "proftpd-basic",
            "binary_version": "1.3.6c-2ubuntu0.1"
        },
        {
            "binary_name": "proftpd-mod-geoip",
            "binary_version": "1.3.6c-2ubuntu0.1"
        },
        {
            "binary_name": "proftpd-mod-ldap",
            "binary_version": "1.3.6c-2ubuntu0.1"
        },
        {
            "binary_name": "proftpd-mod-mysql",
            "binary_version": "1.3.6c-2ubuntu0.1"
        },
        {
            "binary_name": "proftpd-mod-odbc",
            "binary_version": "1.3.6c-2ubuntu0.1"
        },
        {
            "binary_name": "proftpd-mod-pgsql",
            "binary_version": "1.3.6c-2ubuntu0.1"
        },
        {
            "binary_name": "proftpd-mod-snmp",
            "binary_version": "1.3.6c-2ubuntu0.1"
        },
        {
            "binary_name": "proftpd-mod-sqlite",
            "binary_version": "1.3.6c-2ubuntu0.1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-63091.json"
Ubuntu:22.04:LTS
proftpd-dfsg

Package

Name
proftpd-dfsg
Purl
pkg:deb/ubuntu/proftpd-dfsg?arch=source&distro=jammy

Affected ranges

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

Affected versions

1.*
1.3.7b+dfsg-1
1.3.7c+dfsg-1build1
1.3.7c+dfsg-1ubuntu0.1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "proftpd-basic",
            "binary_version": "1.3.7c+dfsg-1ubuntu0.1"
        },
        {
            "binary_name": "proftpd-core",
            "binary_version": "1.3.7c+dfsg-1ubuntu0.1"
        },
        {
            "binary_name": "proftpd-mod-crypto",
            "binary_version": "1.3.7c+dfsg-1ubuntu0.1"
        },
        {
            "binary_name": "proftpd-mod-geoip",
            "binary_version": "1.3.7c+dfsg-1ubuntu0.1"
        },
        {
            "binary_name": "proftpd-mod-ldap",
            "binary_version": "1.3.7c+dfsg-1ubuntu0.1"
        },
        {
            "binary_name": "proftpd-mod-mysql",
            "binary_version": "1.3.7c+dfsg-1ubuntu0.1"
        },
        {
            "binary_name": "proftpd-mod-odbc",
            "binary_version": "1.3.7c+dfsg-1ubuntu0.1"
        },
        {
            "binary_name": "proftpd-mod-pgsql",
            "binary_version": "1.3.7c+dfsg-1ubuntu0.1"
        },
        {
            "binary_name": "proftpd-mod-snmp",
            "binary_version": "1.3.7c+dfsg-1ubuntu0.1"
        },
        {
            "binary_name": "proftpd-mod-sqlite",
            "binary_version": "1.3.7c+dfsg-1ubuntu0.1"
        },
        {
            "binary_name": "proftpd-mod-wrap",
            "binary_version": "1.3.7c+dfsg-1ubuntu0.1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-63091.json"
Ubuntu:24.04:LTS
proftpd-dfsg

Package

Name
proftpd-dfsg
Purl
pkg:deb/ubuntu/proftpd-dfsg?arch=source&distro=noble

Affected ranges

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

Affected versions

1.*
1.3.8+dfsg-8
1.3.8.a+dfsg-1
1.3.8.b+dfsg-1
1.3.8.b+dfsg-1build1
1.3.8.b+dfsg-1build2
1.3.8.b+dfsg-1build3
1.3.8.b+dfsg-1ubuntu0.1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "proftpd-core",
            "binary_version": "1.3.8.b+dfsg-1ubuntu0.1"
        },
        {
            "binary_name": "proftpd-mod-crypto",
            "binary_version": "1.3.8.b+dfsg-1ubuntu0.1"
        },
        {
            "binary_name": "proftpd-mod-geoip",
            "binary_version": "1.3.8.b+dfsg-1ubuntu0.1"
        },
        {
            "binary_name": "proftpd-mod-ldap",
            "binary_version": "1.3.8.b+dfsg-1ubuntu0.1"
        },
        {
            "binary_name": "proftpd-mod-mysql",
            "binary_version": "1.3.8.b+dfsg-1ubuntu0.1"
        },
        {
            "binary_name": "proftpd-mod-odbc",
            "binary_version": "1.3.8.b+dfsg-1ubuntu0.1"
        },
        {
            "binary_name": "proftpd-mod-pgsql",
            "binary_version": "1.3.8.b+dfsg-1ubuntu0.1"
        },
        {
            "binary_name": "proftpd-mod-snmp",
            "binary_version": "1.3.8.b+dfsg-1ubuntu0.1"
        },
        {
            "binary_name": "proftpd-mod-sqlite",
            "binary_version": "1.3.8.b+dfsg-1ubuntu0.1"
        },
        {
            "binary_name": "proftpd-mod-wrap",
            "binary_version": "1.3.8.b+dfsg-1ubuntu0.1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-63091.json"
Ubuntu:26.04:LTS
proftpd-dfsg

Package

Name
proftpd-dfsg
Purl
pkg:deb/ubuntu/proftpd-dfsg?arch=source&distro=resolute

Affected ranges

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

Affected versions

1.*
1.3.9~dfsg-3
1.3.9~dfsg-4

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "proftpd-core",
            "binary_version": "1.3.9~dfsg-4"
        },
        {
            "binary_name": "proftpd-mod-crypto",
            "binary_version": "1.3.9~dfsg-4"
        },
        {
            "binary_name": "proftpd-mod-geoip",
            "binary_version": "1.3.9~dfsg-4"
        },
        {
            "binary_name": "proftpd-mod-ldap",
            "binary_version": "1.3.9~dfsg-4"
        },
        {
            "binary_name": "proftpd-mod-mysql",
            "binary_version": "1.3.9~dfsg-4"
        },
        {
            "binary_name": "proftpd-mod-odbc",
            "binary_version": "1.3.9~dfsg-4"
        },
        {
            "binary_name": "proftpd-mod-pgsql",
            "binary_version": "1.3.9~dfsg-4"
        },
        {
            "binary_name": "proftpd-mod-snmp",
            "binary_version": "1.3.9~dfsg-4"
        },
        {
            "binary_name": "proftpd-mod-sqlite",
            "binary_version": "1.3.9~dfsg-4"
        },
        {
            "binary_name": "proftpd-mod-wrap",
            "binary_version": "1.3.9~dfsg-4"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-63091.json"