Upstream information

CVE-2026-53994 at MITRE

Description

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.

SUSE information

Overall state of this security issue: Pending

This issue is currently rated as having important severity.

CVSS v3 Scores
CVSS detail CNA (VulnCheck) SUSE
Base Score 7.5 7.5
Vector CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Attack Vector Network Network
Attack Complexity High High
Privileges Required Low Low
User Interaction None None
Scope Unchanged Unchanged
Confidentiality Impact High High
Integrity Impact High High
Availability Impact High High
CVSSv3 Version 3.1 3.1
CVSS v4 Scores
CVSS detail CNA (VulnCheck)
Base Score 7.7
Vector 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
Attack Vector Network
Attack Complexity High
Attack Requirements None
Privileges Required Low
User Interaction None
Vulnerable System Confidentiality Impact High
Vulnerable System Integrity Impact High
Vulnerable System Availability Impact High
Subsequent System Confidentiality Impact None
Subsequent System Integrity Impact None
Subsequent System Availability Impact None
CVSSv4 Version 4.0
SUSE Bugzilla entry: 1271946 [NEW]

No SUSE Security Announcements cross referenced.

Status of this issue by product and package

Please note that this evaluation state might be work in progress, incomplete or outdated. Also information for service packs in the LTSS phase is only included for issues meeting the LTSS criteria. If in doubt, feel free to contact us for clarification. The updates are grouped by state of their lifecycle. SUSE product lifecycles are documented on the lifecycle page.

Product(s) Source package State
Products under general support and receiving all security fixes.
SUSE Linux Enterprise High Performance Computing 15 SP7 proftpd Affected
SUSE Linux Enterprise Module for Server Applications 15 SP7 proftpd Affected
SUSE Linux Enterprise Server 15 SP7 proftpd Affected
SUSE Linux Enterprise Server for SAP Applications 15 SP7 proftpd Affected
Products under Long Term Service Pack support and receiving important and critical security fixes.
SUSE Linux Enterprise Module for Server Applications 15 SP6 proftpd Affected
SUSE Linux Enterprise Server 15 SP6 proftpd Affected
SUSE Linux Enterprise Server 15 SP6-LTSS proftpd Affected
SUSE Linux Enterprise Server for SAP Applications 15 SP6 proftpd Affected
Products past their end of life and not receiving proactive updates anymore.
SUSE Linux Enterprise High Performance Computing 15 SP6 proftpd Affected
openSUSE Leap 15.6 proftpd Affected

SUSE Timeline for this CVE

CVE page created: Tue Jul 21 11:35:20 2026
CVE page last modified: Tue Jul 21 11:35:20 2026