DEBIAN-CVE-2026-63091
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.
DEBIAN-CVE-2026-63091
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-2026-63091
proftpd-dfsg
Source reference: /affected/0/package/name
- Affected versions
- 1.3.8+dfsg-4
Source reference:
/affected/0/versions1.3.8+dfsg-4+deb12u1Source reference:
/affected/0/versions1.3.8+dfsg-4+deb12u2Source reference:
/affected/0/versions1.3.8+dfsg-4+deb12u3Source reference:
/affected/0/versions1.3.8+dfsg-4+deb12u4Source reference:
/affected/0/versions1.3.8+dfsg-4+deb12u5Source reference:
/affected/0/versions1.3.8+dfsg-5Source reference:
/affected/0/versions1.3.8+dfsg-6Source reference:
/affected/0/versions1.3.8+dfsg-7Source reference:
/affected/0/versions1.3.8+dfsg-8Source reference:
/affected/0/versions1.3.8.a+dfsg-1Source reference:
/affected/0/versions1.3.8.b+dfsg-1Source reference:
/affected/0/versions1.3.8.b+dfsg-2Source reference:
/affected/0/versions1.3.8.b+dfsg-3Source reference:
/affected/0/versions1.3.8.b+dfsg-4Source reference:
/affected/0/versions1.3.8.c+dfsg-1Source reference:
/affected/0/versions1.3.8.c+dfsg-2Source reference:
/affected/0/versions1.3.8.c+dfsg-3Source reference:
/affected/0/versions1.3.8.c+dfsg-4Source reference:
/affected/0/versions1.3.9a~dfsg-1Source reference:
/affected/0/versions1.3.9b~dfsg-1Source reference:
/affected/0/versions1.3.9c~dfsg-1Source reference:
/affected/0/versions1.3.9d~dfsg-1Source reference:
/affected/0/versions1.3.9~dfsg-1Source reference:
/affected/0/versions1.3.9~dfsg-2Source reference:
/affected/0/versions1.3.9~dfsg-3Source reference:
/affected/0/versions1.3.9~dfsg-4Source reference:
/affected/0/versions1.3.9~dfsg-5Source reference:
/affected/0/versions - Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
proftpd-dfsg
Source reference: /affected/1/package/name
- Affected versions
- 1.3.8.c+dfsg-4
Source reference:
/affected/1/versions1.3.8.c+dfsg-4+deb13u1Source reference:
/affected/1/versions1.3.8.c+dfsg-4+deb13u2Source reference:
/affected/1/versions - Fixed versions
- 1.3.8.c+dfsg-4+deb13u3
Source reference:
/affected/1/ranges - Prerequisites
- Not stated in this record
proftpd-dfsg
Source reference: /affected/2/package/name
- Affected versions
- 1.3.8.c+dfsg-4
Source reference:
/affected/2/versions1.3.9a~dfsg-1Source reference:
/affected/2/versions1.3.9b~dfsg-1Source reference:
/affected/2/versions1.3.9~dfsg-1Source reference:
/affected/2/versions1.3.9~dfsg-2Source reference:
/affected/2/versions1.3.9~dfsg-3Source reference:
/affected/2/versions1.3.9~dfsg-4Source reference:
/affected/2/versions1.3.9~dfsg-5Source reference:
/affected/2/versions - Fixed versions
- 1.3.9c~dfsg-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"
}
]
}
],
"package": {
"name": "proftpd-dfsg",
"purl": "pkg:deb/debian/proftpd-dfsg?arch=source&distro=bookworm",
"ecosystem": "Debian:12"
},
"versions": [
"1.3.8+dfsg-4",
"1.3.8+dfsg-4+deb12u1",
"1.3.8+dfsg-4+deb12u2",
"1.3.8+dfsg-4+deb12u3",
"1.3.8+dfsg-4+deb12u4",
"1.3.8+dfsg-4+deb12u5",
"1.3.8+dfsg-5",
"1.3.8+dfsg-6",
"1.3.8+dfsg-7",
"1.3.8+dfsg-8",
"1.3.8.a+dfsg-1",
"1.3.8.b+dfsg-1",
"1.3.8.b+dfsg-2",
"1.3.8.b+dfsg-3",
"1.3.8.b+dfsg-4",
"1.3.8.c+dfsg-1",
"1.3.8.c+dfsg-2",
"1.3.8.c+dfsg-3",
"1.3.8.c+dfsg-4",
"1.3.9a~dfsg-1",
"1.3.9b~dfsg-1",
"1.3.9c~dfsg-1",
"1.3.9d~dfsg-1",
"1.3.9~dfsg-1",
"1.3.9~dfsg-2",
"1.3.9~dfsg-3",
"1.3.9~dfsg-4",
"1.3.9~dfsg-5"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-63091.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "1.3.8.c+dfsg-4+deb13u3"
}
]
}
],
"package": {
"name": "proftpd-dfsg",
"purl": "pkg:deb/debian/proftpd-dfsg?arch=source&distro=trixie",
"ecosystem": "Debian:13"
},
"versions": [
"1.3.8.c+dfsg-4",
"1.3.8.c+dfsg-4+deb13u1",
"1.3.8.c+dfsg-4+deb13u2"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-63091.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "1.3.9c~dfsg-1"
}
]
}
],
"package": {
"name": "proftpd-dfsg",
"purl": "pkg:deb/debian/proftpd-dfsg?arch=source&distro=forky",
"ecosystem": "Debian:14"
},
"versions": [
"1.3.8.c+dfsg-4",
"1.3.9a~dfsg-1",
"1.3.9b~dfsg-1",
"1.3.9~dfsg-1",
"1.3.9~dfsg-2",
"1.3.9~dfsg-3",
"1.3.9~dfsg-4",
"1.3.9~dfsg-5"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-63091.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
}
]Publisher severity
No explicit severity was provided.
- Event
- #58104 · Revision 1
- Added to Heist Feed
- Publisher date