CVE-2026-63091

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Source
https://cve.org/CVERecord?id=CVE-2026-63091
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-63091.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-63091
Downstream
Published
2026-07-20T14:22:29.202Z
Modified
2026-08-07T22:16:28.434801Z
Severity
  • 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
Summary
ProFTPD mod_sftp Signed Integer Overflow via SCP Size-Record Parser
Details

ProFTPD before 1.3.9c and 1.3.10rc3 contains a signed integer overflow vulnerability in the modsftp module's SCP size-record parser that allows authenticated low-privilege attackers to bypass ASLR by sending a crafted file size value of UINT64MAX, which results in a negative offt value. Attackers can exploit the subsequent conversion to uint32t, 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.

Database specific 
{
    "cna_assigner": "VulnCheck",
    "cwe_ids": [
        "CWE-126",
        "CWE-190"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/63xxx/CVE-2026-63091.json"
}
References

Affected packages

Git / github.com/proftpd/proftpd

Affected ranges

Type
GIT
Repo
https://github.com/proftpd/proftpd
Events
Introduced
0 Unknown introduced commit / All previous commits are affected
Fixed
78a1bea439969913d7002bfb16ee7f0f60e262b4
Introduced
df75a382880e68d8c0f252cf930a7d78c57a9f6f
Fixed
b9b7dde1bcd74bc23366484d53856b67b8d6d95e
Fixed
dbf20f70159ba62f840a9d4347569259b2ecfeba
Database specific 
{
    "source": [
        "CPE_RANGE",
        "CPE_STRING",
        "REFERENCES"
    ],
    "cpe": [
        "cpe:2.3:a:proftpd:proftpd:*:*:*:*:*:*:*:*",
        "cpe:2.3:a:proftpd:proftpd:1.3.10:rc1:*:*:*:*:*:*",
        "cpe:2.3:a:proftpd:proftpd:1.3.10:rc2:*:*:*:*:*:*"
    ],
    "extracted_events": [
        {
            "introduced": "0"
        },
        {
            "fixed": "1.3.9c"
        },
        {
            "introduced": "1.3.10-rc1"
        },
        {
            "last_affected": "1.3.10-rc1"
        },
        {
            "introduced": "1.3.10-rc2"
        },
        {
            "last_affected": "1.3.10-rc2"
        }
    ]
}

Affected versions

1.*
1.3.10-rc1
1.3.10-rc2
v1.*
v1.3.10rc1
v1.3.10rc2
v1.3.10rc2-2
v1.3.6
v1.3.6rc1
v1.3.6rc2
v1.3.6rc3
v1.3.6rc4
v1.3.7
v1.3.7rc1
v1.3.7rc2
v1.3.7rc3
v1.3.7rc4
v1.3.8
v1.3.8rc1
v1.3.8rc2
v1.3.8rc3
v1.3.8rc4
v1.3.9
v1.3.9a
v1.3.9b
v1.3.9rc1
v1.3.9rc2
v1.3.9rc3

Database specific

vanir_signatures_modified 
"2026-08-07T22:16:28Z"
vanir_signatures 
[
    {
        "target": {
            "function": "recv_filesz",
            "file": "contrib/mod_sftp/scp.c"
        },
        "digest": {
            "length": 560.0,
            "function_hash": "44465721554834838967954885988293477133"
        },
        "signature_version": "v1",
        "signature_type": "Function",
        "deprecated": false,
        "id": "CVE-2026-63091-a94f1acd",
        "source": "https://github.com/proftpd/proftpd/commit/b9b7dde1bcd74bc23366484d53856b67b8d6d95e"
    },
    {
        "target": {
            "file": "contrib/mod_sftp/scp.c"
        },
        "digest": {
            "line_hashes": [
                "211356360216240580586823575764788770154",
                "64185466759012605714086153750060625383",
                "105303355871983037325147577682023285130",
                "187249558005387688938343368974739548144",
                "133940347888088264145019385675761806942",
                "217803762710867372129974155698965325129",
                "53241196232858055262156629608988596532",
                "121513144656691475959960427367711908285",
                "317375272226865273816334196016139068013"
            ],
            "threshold": 0.9
        },
        "signature_version": "v1",
        "signature_type": "Line",
        "deprecated": false,
        "id": "CVE-2026-63091-b44939cf",
        "source": "https://github.com/proftpd/proftpd/commit/b9b7dde1bcd74bc23366484d53856b67b8d6d95e"
    }
]
source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-63091.json"