CVE catalog
CVE-2026-53994
ProFTPD mod_sftp contains a heap-based buffer overflow reachable by an authenticated SFTP user. The fxp_packet_read() function accepts the attacker-supplied 32-bit big-endian SFTP packet length withou
- Severity
- High · CVSS 7.7
CVSS:4.0/AV:N/AC:H/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - Published
- Source
- [NVD] · [CVE record]
- EPSS
- 0.45% · Oct 25, 2026
ProFTPD mod_sftp contains a heap-based buffer overflow reachable by an authenticated SFTP user. The fxp_packet_read() function accepts the attacker-supplied 32-bit big-endian SFTP packet length without a minimum sanity check. A value of 0 causes an unsigned subtraction elsewhere in the read path to underflow to approximately 4 GB. That oversized request reaches the core memory allocator, where the rounded size is computed in size_t but passed to new_block() as a 32-bit int; the low 32 bits of 0x100000000 are 0, so new_block() returns a small (~512-byte) block while the caller is told it received ~4 GB. The subsequent fill loop then streams attacker-controlled bytes past the end of the 544-byte allocation, producing an attacker-controlled heap buffer overflow. An authenticated user can crash the per-connection ProFTPD session child on demand with a single malformed SFTP packet (packet_len=0 followed by a body greater than approximately 544 bytes), producing reliable authenticated remote denial of service. Depending on heap layout and adjacent allocations, heap metadata corruption and further consequences beyond denial of service may be possible, though only denial of service is demonstrated by the supplied proof of concept.
Vulnerable and fixed packages
Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.
| Distribution | Package | Release | Version | Status |
|---|---|---|---|---|
| Debian | proftpd-dfsg | sid | 1.3.9e~dfsg-1 | fixed |
| Debian | proftpd-dfsg | forky | 1.3.9d~dfsg-1 | fixed |
| Debian | proftpd-dfsg | trixie | 1.3.8.c+dfsg-4+deb13u3 | fixed |
| Debian | proftpd-dfsg | bookworm | 1.3.8+dfsg-4+deb12u5 | vulnerable |
| Debian | proftpd-dfsg | bookworm-security | 1.3.8+dfsg-4+deb12u4 | vulnerable |
| Cpe | proftpd-dfsg | Not reported | Not reported | vulnerable |
| Ubuntu | proftpd-dfsg | 16.04 | 1.3.5-2 | vulnerable |
| Ubuntu | proftpd-dfsg | 16.04 | 1.3.5a-1 | vulnerable |
| Ubuntu | proftpd-dfsg | 16.04 | 1.3.5a-1build1 | vulnerable |
| Ubuntu | proftpd-dfsg | 16.04 | 1.3.5a-1ubuntu0.1 | vulnerable |
| Ubuntu | proftpd-dfsg | 18.04 | 1.3.5d-1 | vulnerable |
| Ubuntu | proftpd-dfsg | 18.04 | 1.3.5e-1build1 | vulnerable |
| Ubuntu | proftpd-dfsg | 20.04 | 1.3.6-6build2 | vulnerable |
| Ubuntu | proftpd-dfsg | 20.04 | 1.3.6c-1 | vulnerable |
| Ubuntu | proftpd-dfsg | 20.04 | 1.3.6c-2 | vulnerable |
| Ubuntu | proftpd-dfsg | 20.04 | 1.3.6c-2ubuntu0.1 | vulnerable |
| Ubuntu | proftpd-dfsg | 22.04 | 1.3.7b+dfsg-1 | vulnerable |
| Ubuntu | proftpd-dfsg | 22.04 | 1.3.7c+dfsg-1build1 | vulnerable |
| Ubuntu | proftpd-dfsg | 22.04 | 1.3.7c+dfsg-1ubuntu0.1 | vulnerable |
| Ubuntu | proftpd-dfsg | 24.04 | 1.3.8+dfsg-8 | vulnerable |
| Ubuntu | proftpd-dfsg | 24.04 | 1.3.8.a+dfsg-1 | vulnerable |
| Ubuntu | proftpd-dfsg | 24.04 | 1.3.8.b+dfsg-1 | vulnerable |
| Ubuntu | proftpd-dfsg | 24.04 | 1.3.8.b+dfsg-1build1 | vulnerable |
| Ubuntu | proftpd-dfsg | 24.04 | 1.3.8.b+dfsg-1build2 | vulnerable |
| Ubuntu | proftpd-dfsg | 24.04 | 1.3.8.b+dfsg-1build3 | vulnerable |
| Ubuntu | proftpd-dfsg | 24.04 | 1.3.8.b+dfsg-1ubuntu0.1 | vulnerable |
| Ubuntu | proftpd-dfsg | 26.04 | 1.3.9~dfsg-3 | vulnerable |
| Ubuntu | proftpd-dfsg | 26.04 | 1.3.9~dfsg-4 | vulnerable |
| Cpe | proftpd | Not reported | 1.3.10 | fixed |
Fixed-version evidence
| Distribution | Package | Type | Release | Fixed version | Urgency | Origin | Bugs |
|---|---|---|---|---|---|---|---|
| Debian | proftpd-dfsg | source | sid | 1.3.9b~dfsg-1 | not yet assigned | Not reported | Not reported |
| Debian | proftpd-dfsg | source | forky | 1.3.9b~dfsg-1 | not yet assigned | Not reported | Not reported |
| Debian | proftpd-dfsg | source | trixie | 1.3.8.c+dfsg-4+deb13u3 | not yet assigned | Not reported | Not reported |
| Debian | proftpd-dfsg | source | bookworm | (unfixed) | not yet assigned | Not reported | Not reported |
| Cpe | proftpd | cpe | Not reported | 1.3.10 | Not reported | NVD-CVE-2026-53994 | Not reported |
OpenFactory catalog packages
[Debian 12 (Bookworm)]
- [proftpd-basic]Affected
Source package: [proftpd-dfsg]
Details (4)
1.3.8+dfsg-4+deb12u5· all · bookwormAffected
nvd · proftpd-dfsg · debian · bookworm; nvd · proftpd-dfsg · debian · 12
1.3.8+dfsg-4+deb12u5· all · bookwormAffected
nvd · proftpd-dfsg · debian · bookworm; nvd · proftpd-dfsg · debian · 12
1.3.8+dfsg-4+deb12u4· all · bookworm-securityAffected
nvd · proftpd-dfsg · debian · bookworm; nvd · proftpd-dfsg · debian · 12
1.3.8+dfsg-4+deb12u4· all · bookworm-securityAffected
nvd · proftpd-dfsg · debian · bookworm; nvd · proftpd-dfsg · debian · 12
- [proftpd-core]Affected
Source package: [proftpd-dfsg]
Details (4)
1.3.8+dfsg-4+deb12u5· amd64 · bookwormAffected
nvd · proftpd-dfsg · debian · bookworm; nvd · proftpd-dfsg · debian · 12
1.3.8+dfsg-4+deb12u5· arm64 · bookwormAffected
nvd · proftpd-dfsg · debian · bookworm; nvd · proftpd-dfsg · debian · 12
1.3.8+dfsg-4+deb12u4· amd64 · bookworm-securityAffected
nvd · proftpd-dfsg · debian · bookworm; nvd · proftpd-dfsg · debian · 12
1.3.8+dfsg-4+deb12u4· arm64 · bookworm-securityAffected
nvd · proftpd-dfsg · debian · bookworm; nvd · proftpd-dfsg · debian · 12
- [proftpd-dev]Affected
Source package: [proftpd-dfsg]
Details (4)
1.3.8+dfsg-4+deb12u5· amd64 · bookwormAffected
nvd · proftpd-dfsg · debian · bookworm; nvd · proftpd-dfsg · debian · 12
1.3.8+dfsg-4+deb12u5· arm64 · bookwormAffected
nvd · proftpd-dfsg · debian · bookworm; nvd · proftpd-dfsg · debian · 12
1.3.8+dfsg-4+deb12u4· amd64 · bookworm-securityAffected
nvd · proftpd-dfsg · debian · bookworm; nvd · proftpd-dfsg · debian · 12
1.3.8+dfsg-4+deb12u4· arm64 · bookworm-securityAffected
nvd · proftpd-dfsg · debian · bookworm; nvd · proftpd-dfsg · debian · 12
- [proftpd-doc]Affected
Source package: [proftpd-dfsg]
Details (4)
1.3.8+dfsg-4+deb12u5· all · bookwormAffected
nvd · proftpd-dfsg · debian · bookworm; nvd · proftpd-dfsg · debian · 12
1.3.8+dfsg-4+deb12u5· all · bookwormAffected
nvd · proftpd-dfsg · debian · bookworm; nvd · proftpd-dfsg · debian · 12
1.3.8+dfsg-4+deb12u4· all · bookworm-securityAffected
nvd · proftpd-dfsg · debian · bookworm; nvd · proftpd-dfsg · debian · 12
1.3.8+dfsg-4+deb12u4· all · bookworm-securityAffected
nvd · proftpd-dfsg · debian · bookworm; nvd · proftpd-dfsg · debian · 12
- [proftpd-mod-crypto]Affected
Source package: [proftpd-dfsg]
Details (4)
1.3.8+dfsg-4+deb12u5· amd64 · bookwormAffected
nvd · proftpd-dfsg · debian · bookworm; nvd · proftpd-dfsg · debian · 12
1.3.8+dfsg-4+deb12u5· arm64 · bookwormAffected
nvd · proftpd-dfsg · debian · bookworm; nvd · proftpd-dfsg · debian · 12
1.3.8+dfsg-4+deb12u4· amd64 · bookworm-securityAffected
nvd · proftpd-dfsg · debian · bookworm; nvd · proftpd-dfsg · debian · 12
1.3.8+dfsg-4+deb12u4· arm64 · bookworm-securityAffected
nvd · proftpd-dfsg · debian · bookworm; nvd · proftpd-dfsg · debian · 12
- [proftpd-mod-geoip]Affected
Source package: [proftpd-dfsg]
Details (4)
1.3.8+dfsg-4+deb12u5· amd64 · bookwormAffected
nvd · proftpd-dfsg · debian · bookworm; nvd · proftpd-dfsg · debian · 12
1.3.8+dfsg-4+deb12u5· arm64 · bookwormAffected
nvd · proftpd-dfsg · debian · bookworm; nvd · proftpd-dfsg · debian · 12
1.3.8+dfsg-4+deb12u4· amd64 · bookworm-securityAffected
nvd · proftpd-dfsg · debian · bookworm; nvd · proftpd-dfsg · debian · 12
1.3.8+dfsg-4+deb12u4· arm64 · bookworm-securityAffected
nvd · proftpd-dfsg · debian · bookworm; nvd · proftpd-dfsg · debian · 12
- [proftpd-mod-ldap]Affected
Source package: [proftpd-dfsg]
Details (4)
1.3.8+dfsg-4+deb12u5· amd64 · bookwormAffected
nvd · proftpd-dfsg · debian · bookworm; nvd · proftpd-dfsg · debian · 12
1.3.8+dfsg-4+deb12u5· arm64 · bookwormAffected
nvd · proftpd-dfsg · debian · bookworm; nvd · proftpd-dfsg · debian · 12
1.3.8+dfsg-4+deb12u4· amd64 · bookworm-securityAffected
nvd · proftpd-dfsg · debian · bookworm; nvd · proftpd-dfsg · debian · 12
1.3.8+dfsg-4+deb12u4· arm64 · bookworm-securityAffected
nvd · proftpd-dfsg · debian · bookworm; nvd · proftpd-dfsg · debian · 12
- [proftpd-mod-mysql]Affected
Source package: [proftpd-dfsg]
Details (4)
1.3.8+dfsg-4+deb12u5· amd64 · bookwormAffected
nvd · proftpd-dfsg · debian · bookworm; nvd · proftpd-dfsg · debian · 12
1.3.8+dfsg-4+deb12u5· arm64 · bookwormAffected
nvd · proftpd-dfsg · debian · bookworm; nvd · proftpd-dfsg · debian · 12
1.3.8+dfsg-4+deb12u4· amd64 · bookworm-securityAffected
nvd · proftpd-dfsg · debian · bookworm; nvd · proftpd-dfsg · debian · 12
1.3.8+dfsg-4+deb12u4· arm64 · bookworm-securityAffected
nvd · proftpd-dfsg · debian · bookworm; nvd · proftpd-dfsg · debian · 12
- [proftpd-mod-odbc]Affected
Source package: [proftpd-dfsg]
Details (4)
1.3.8+dfsg-4+deb12u5· amd64 · bookwormAffected
nvd · proftpd-dfsg · debian · bookworm; nvd · proftpd-dfsg · debian · 12
1.3.8+dfsg-4+deb12u5· arm64 · bookwormAffected
nvd · proftpd-dfsg · debian · bookworm; nvd · proftpd-dfsg · debian · 12
1.3.8+dfsg-4+deb12u4· amd64 · bookworm-securityAffected
nvd · proftpd-dfsg · debian · bookworm; nvd · proftpd-dfsg · debian · 12
1.3.8+dfsg-4+deb12u4· arm64 · bookworm-securityAffected
nvd · proftpd-dfsg · debian · bookworm; nvd · proftpd-dfsg · debian · 12
- [proftpd-mod-pgsql]Affected
Source package: [proftpd-dfsg]
Details (4)
1.3.8+dfsg-4+deb12u5· amd64 · bookwormAffected
nvd · proftpd-dfsg · debian · bookworm; nvd · proftpd-dfsg · debian · 12
1.3.8+dfsg-4+deb12u5· arm64 · bookwormAffected
nvd · proftpd-dfsg · debian · bookworm; nvd · proftpd-dfsg · debian · 12
1.3.8+dfsg-4+deb12u4· amd64 · bookworm-securityAffected
nvd · proftpd-dfsg · debian · bookworm; nvd · proftpd-dfsg · debian · 12
1.3.8+dfsg-4+deb12u4· arm64 · bookworm-securityAffected
nvd · proftpd-dfsg · debian · bookworm; nvd · proftpd-dfsg · debian · 12
- [proftpd-mod-snmp]Affected
Source package: [proftpd-dfsg]
Details (4)
1.3.8+dfsg-4+deb12u5· amd64 · bookwormAffected
nvd · proftpd-dfsg · debian · bookworm; nvd · proftpd-dfsg · debian · 12
1.3.8+dfsg-4+deb12u5· arm64 · bookwormAffected
nvd · proftpd-dfsg · debian · bookworm; nvd · proftpd-dfsg · debian · 12
1.3.8+dfsg-4+deb12u4· amd64 · bookworm-securityAffected
nvd · proftpd-dfsg · debian · bookworm; nvd · proftpd-dfsg · debian · 12
1.3.8+dfsg-4+deb12u4· arm64 · bookworm-securityAffected
nvd · proftpd-dfsg · debian · bookworm; nvd · proftpd-dfsg · debian · 12
- [proftpd-mod-sqlite]Affected
Source package: [proftpd-dfsg]
Details (4)
1.3.8+dfsg-4+deb12u5· amd64 · bookwormAffected
nvd · proftpd-dfsg · debian · bookworm; nvd · proftpd-dfsg · debian · 12
1.3.8+dfsg-4+deb12u5· arm64 · bookwormAffected
nvd · proftpd-dfsg · debian · bookworm; nvd · proftpd-dfsg · debian · 12
1.3.8+dfsg-4+deb12u4· amd64 · bookworm-securityAffected
nvd · proftpd-dfsg · debian · bookworm; nvd · proftpd-dfsg · debian · 12
1.3.8+dfsg-4+deb12u4· arm64 · bookworm-securityAffected
nvd · proftpd-dfsg · debian · bookworm; nvd · proftpd-dfsg · debian · 12
- [proftpd-mod-wrap]Affected
Source package: [proftpd-dfsg]
Details (4)
1.3.8+dfsg-4+deb12u5· amd64 · bookwormAffected
nvd · proftpd-dfsg · debian · bookworm; nvd · proftpd-dfsg · debian · 12
1.3.8+dfsg-4+deb12u5· arm64 · bookwormAffected
nvd · proftpd-dfsg · debian · bookworm; nvd · proftpd-dfsg · debian · 12
1.3.8+dfsg-4+deb12u4· amd64 · bookworm-securityAffected
nvd · proftpd-dfsg · debian · bookworm; nvd · proftpd-dfsg · debian · 12
1.3.8+dfsg-4+deb12u4· arm64 · bookworm-securityAffected
nvd · proftpd-dfsg · debian · bookworm; nvd · proftpd-dfsg · debian · 12
[Debian 13 (Trixie)]
- [proftpd-core]Affected
Source package: [proftpd-dfsg]
Details (2)
1.3.8.c+dfsg-4+deb13u2· amd64 · trixieAffected · Fixed:
1.3.8.c+dfsg-4+deb13u3nvd · proftpd-dfsg · debian · 13
1.3.8.c+dfsg-4+deb13u2· arm64 · trixieAffected · Fixed:
1.3.8.c+dfsg-4+deb13u3nvd · proftpd-dfsg · debian · 13
- [proftpd-dev]Affected
Source package: [proftpd-dfsg]
Details (2)
1.3.8.c+dfsg-4+deb13u2· amd64 · trixieAffected · Fixed:
1.3.8.c+dfsg-4+deb13u3nvd · proftpd-dfsg · debian · 13
1.3.8.c+dfsg-4+deb13u2· arm64 · trixieAffected · Fixed:
1.3.8.c+dfsg-4+deb13u3nvd · proftpd-dfsg · debian · 13
- [proftpd-doc]Affected
Source package: [proftpd-dfsg]
Details (2)
1.3.8.c+dfsg-4+deb13u2· all · trixieAffected · Fixed:
1.3.8.c+dfsg-4+deb13u3nvd · proftpd-dfsg · debian · 13
1.3.8.c+dfsg-4+deb13u2· all · trixieAffected · Fixed:
1.3.8.c+dfsg-4+deb13u3nvd · proftpd-dfsg · debian · 13
- [proftpd-mod-crypto]Affected
Source package: [proftpd-dfsg]
Details (2)
1.3.8.c+dfsg-4+deb13u2· amd64 · trixieAffected · Fixed:
1.3.8.c+dfsg-4+deb13u3nvd · proftpd-dfsg · debian · 13
1.3.8.c+dfsg-4+deb13u2· arm64 · trixieAffected · Fixed:
1.3.8.c+dfsg-4+deb13u3nvd · proftpd-dfsg · debian · 13
- [proftpd-mod-geoip]Affected
Source package: [proftpd-dfsg]
Details (2)
1.3.8.c+dfsg-4+deb13u2· amd64 · trixieAffected · Fixed:
1.3.8.c+dfsg-4+deb13u3nvd · proftpd-dfsg · debian · 13
1.3.8.c+dfsg-4+deb13u2· arm64 · trixieAffected · Fixed:
1.3.8.c+dfsg-4+deb13u3nvd · proftpd-dfsg · debian · 13
- [proftpd-mod-ldap]Affected
Source package: [proftpd-dfsg]
Details (2)
1.3.8.c+dfsg-4+deb13u2· amd64 · trixieAffected · Fixed:
1.3.8.c+dfsg-4+deb13u3nvd · proftpd-dfsg · debian · 13
1.3.8.c+dfsg-4+deb13u2· arm64 · trixieAffected · Fixed:
1.3.8.c+dfsg-4+deb13u3nvd · proftpd-dfsg · debian · 13
- [proftpd-mod-mysql]Affected
Source package: [proftpd-dfsg]
Details (2)
1.3.8.c+dfsg-4+deb13u2· amd64 · trixieAffected · Fixed:
1.3.8.c+dfsg-4+deb13u3nvd · proftpd-dfsg · debian · 13
1.3.8.c+dfsg-4+deb13u2· arm64 · trixieAffected · Fixed:
1.3.8.c+dfsg-4+deb13u3nvd · proftpd-dfsg · debian · 13
Observed:
References
- [https://github.com/proftpd/proftpd]
- [https://github.com/proftpd/proftpd/commit/7342836fa98e36209660a4c5805c801476f63936]
- [https://nvd.nist.gov/vuln/detail/CVE-2026-53994]
- [https://osv.dev/vulnerability/DEBIAN-CVE-2026-53994]
- [https://osv.dev/vulnerability/UBUNTU-CVE-2026-53994]
- [https://security-tracker.debian.org/tracker/CVE-2026-53994]
- [https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-53994.json]
- [https://wid.cert-bund.de/.well-known/csaf/white/2026/wid-sec-w-2026-2406.json]
- [https://www.vulncheck.com/advisories/proftpd-mod-sftp-heap-buffer-overflow-via-unsigned-integer-underflow-and-size-truncation]
[CERT-Bund public advisories] · [Debian Security Tracker] · [FIRST EPSS] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX]