VulnerabilityPublished 19 Oct 2025Updated 24 Feb 2026

CVE-2025-11947: bftpd · Heap-based Buffer Overflow

Affects bftpdSource CVE Database V5

Public exploit available · CVSS 2.0 Low.

Data as of 26 Oct 2026, 10:12 UTC

CVSS 4.0 base score

2.0Low

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.1% chance of exploitation in 30 days – higher than 7% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:4.0/AV:L/AC:H/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P

Base metrics

Attack Vector: Local
Attack Complexity: High
Attack Requirements: None
Privileges Required: Low
User Interaction: None
Vulnerable system confidentiality: Low
Vulnerable system integrity: Low
Vulnerable system availability: Low
Subsequent system confidentiality: None
Subsequent system integrity: None
Subsequent system availability: None

Threat metrics

Exploit Maturity: POC

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Local: The vulnerable system is not bound to the network stack and the attacker’s path is via read/write/execute capabilities. Either the attacker exploits the vulnerability by accessing the target system locally (e.g., keyboard, console), or through terminal emulation (e.g., SSH); or the attacker relies on User Interaction by another person to perform actions required to exploit the vulnerability (e.g., using social engineering techniques to trick a legitimate user into opening a malicious document).
Attack Complexity: High: The successful attack depends on the evasion or circumvention of security-enhancing techniques in place that would otherwise hinder the attack. These include: Evasion of exploit mitigation techniques, for example, circumvention of address space randomization (ASLR) or data execution prevention (DEP) must be performed for the attack to be successful; Obtaining target-specific secrets. The attacker must gather some target-specific secret before the attack can be successful. A secret is any piece of information that cannot be obtained through any amount of reconnaissance. To obtain the secret the attacker must perform additional attacks or break otherwise secure measures (e.g. knowledge of a secret key may be needed to break a crypto channel). This operation must be performed for each attacked target.
Attack Requirements: None: The successful attack does not depend on the deployment and execution conditions of the vulnerable system. The attacker can expect to be able to reach the vulnerability and execute the exploit under all or most instances of the vulnerability.
Privileges Required: Low: The attacker requires privileges that provide basic capabilities that are typically limited to settings and resources owned by a single low-privileged user. Alternatively, an attacker with Low privileges has the ability to access only non-sensitive resources.
User Interaction: None: The vulnerable system can be exploited without interaction from any human user, other than the attacker.
Vulnerable system confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the Vulnerable System.
Vulnerable system integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact to the Vulnerable System.
Vulnerable system availability: Low: Performance is reduced or there are interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the Vulnerable System are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to the Vulnerable System.
Subsequent system confidentiality: None: There is no loss of confidentiality within the Subsequent System or all confidentiality impact is constrained to the Vulnerable System.
Subsequent system integrity: None: There is no loss of integrity within the Subsequent System or all integrity impact is constrained to the Vulnerable System.
Subsequent system availability: None: There is no impact to availability within the Subsequent System or all availability impact is constrained to the Vulnerable System.
Exploit Maturity: POC: Based on threat intelligence sources each of the following must apply: · Proof-of-concept is publicly available · No knowledge of reported attempts to exploit this vulnerability · No knowledge of publicly available solutions used to simplify attempts to exploit the vulnerability

Definitions: FIRST CVSS v4.0 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 19 Oct 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: evidence found.
CVSS exploit maturity: proof of concept public
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), CVSS vector, the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
GitHubbftpd`pkg:github/bftpd`Other threats	Affected =6.0 =6.1 =6.2	Fixed in–

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AI-suggested

Since no official patches or vendor responses are available, organizations should implement the following mitigations: 1) Restrict local access to systems running bftpd to trusted users only, minimizing the risk of local exploitation. 2) Employ strict access controls and monitoring on FTP servers to detect unusual activities or attempts to manipulate configuration files. 3) Consider replacing bftpd with more actively maintained FTP server software that receives timely security updates. 4) Use application-level sandboxing or containerization to limit the impact of any potential exploit. 5) Regularly audit and harden system configurations to reduce attack surfaces, including disabling unnecessary services and accounts. 6) Monitor public vulnerability and exploit databases for updates or new patches related to this CVE. 7) If feasible, implement host-based intrusion detection systems (HIDS) to alert on suspicious memory or process behavior related to bftpd. 8) Educate system administrators about the risks of local privilege escalation vulnerabilities and enforce strong local user account policies.

Description

A weakness has been identified in bftpd up to 6.2. Impacted is the function expand_groups of the file options.c of the component Configuration File Handler. Executing a manipulation can lead to heap-based buffer overflow. It is possible to launch the attack on the local host. Attacks of this nature are highly complex. The exploitability is considered difficult. The exploit has been made available to the public and could be used for attacks. The vendor was contacted early about this disclosure but did not respond in any way.

Impact

The primary impact of CVE-2025-11947 is the potential for local attackers with low privileges to cause heap memory corruption in bftpd, which could lead to arbitrary code execution or denial of service. While the CVSS score is low, the presence of a public exploit increases the risk that skilled attackers could leverage this vulnerability in targeted attacks, especially in environments where local access is possible, such as multi-user systems or shared hosting. The vulnerability does not directly affect confidentiality or integrity on a large scale but could be a stepping stone for privilege escalation or lateral movement within a network. Organizations relying on bftpd for FTP services, particularly in legacy or specialized systems, may face service disruptions or compromise if exploited. The lack of vendor patches and the complexity of exploitation reduce the likelihood of widespread attacks but do not eliminate risk, especially in sensitive or high-security environments.

Summary

CVE-2025-11947 is a heap-based buffer overflow vulnerability identified in the bftpd FTP server software, specifically in the expand_groups function located in the options.c source file, which handles configuration file parsing. The vulnerability affects bftpd versions 6.0, 6.1, and 6.2. The flaw occurs when the function processes group expansion in configuration files, allowing crafted input to overflow heap memory buffers. This can lead to memory corruption, potentially enabling an attacker to execute arbitrary code or cause a denial of service. However, exploitation requires local access with low privileges, and the attack complexity is high, meaning it is difficult to exploit successfully. No user interaction is required, and the vulnerability does not affect system confidentiality, integrity, or availability significantly, as indicated by the CVSS 4.0 vector (AV:L/AC:H/PR:L/UI:N/VC:L/VI:L/VA:L). The vendor was notified early but did not respond or provide patches, and no official fixes are currently available. A public exploit has been released, increasing the risk of exploitation despite the difficulty. The vulnerability is limited to local attacks, reducing its scope but still posing a threat in environments where local user accounts are accessible or where attackers have gained limited access. The lack of vendor response and patch availability necessitates that organizations implement alternative mitigations to reduce risk.

References

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