VulnerabilityPublished 16 Jun 2024Updated 3 Nov 2025

CVE-2024-38440: netatalk · Off-by-one Error

Affects netatalkSource CVE Database V5

Not known to be exploited · CVSS 7.5 High : upgrade to 3.2.1 soon.

Data as of 26 Oct 2026, 14:05 UTC

CVSS 3.1 base score

7.5High

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

EPSS: 0.8% chance of exploitation in 30 days – higher than 58% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 3.2.1

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: High

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

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: High: There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 16 Jun 2024
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
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), 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

Upgrade netatalk/netatalk to 3.2.1.

Affected software

Product	Affected	Fixed in
GitHubnetatalk/netatalk`pkg:github/netatalk/netatalk`Other threats	Affected <3.2.1	Fixed in 3.2.1

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

The most effective mitigation is to upgrade Netatalk to version 3.2.1 or later, or apply patches backported in versions 2.4.1 and 3.1.19. Organizations should audit their environments to identify all Netatalk instances, including embedded systems and NAS devices that may use it. If immediate patching is not feasible, administrators can temporarily disable AFP services or restrict network access to the AFP port (548) using firewalls or network segmentation to limit exposure. Monitoring AFP daemon logs for crashes or unusual activity can help detect exploitation attempts. Additionally, applying heap hardening and memory protection techniques (e.g., ASLR, heap canaries) at the OS level can reduce the risk of successful exploitation. Regular vulnerability scanning and penetration testing targeting AFP services should be incorporated into security programs. Finally, organizations should maintain an inventory of legacy protocols in use and plan migration to more secure file sharing alternatives where possible.

Description

Netatalk before 3.2.1 has an off-by-one error, and resultant heap-based buffer overflow and segmentation violation, because of incorrectly using FPLoginExt in BN_bin2bn in etc/uams/uams_dhx_pam.c. The original issue 1097 report stated: 'The latest version of Netatalk (v3.2.0) contains a security vulnerability. This vulnerability arises due to a lack of validation for the length field after parsing user-provided data, leading to an out-of-bounds heap write of one byte (\0). Under specific configurations, this can result in reading metadata of the next heap block, potentially causing a Denial of Service (DoS) under certain heap layouts or with ASAN enabled. ... The vulnerability is located in the FPLoginExt operation of Netatalk, in the BN_bin2bn function found in /etc/uams/uams_dhx_pam.c ... if (!(bn = BN_bin2bn((unsigned char *)ibuf, KEYSIZE, NULL))) ... threads ... [#0] Id 1, Name: "afpd", stopped 0x7ffff4304e58 in ?? (), reason: SIGSEGV ... [#0] 0x7ffff4304e58 mov BYTE PTR [r14+0x8], 0x0 ... mov rdx, QWORD PTR [rsp+0x18] ... afp_login_ext(obj=<optimized out>, ibuf=0x62d000010424 "", ibuflen=0xffffffffffff0015, rbuf=<optimized out>, rbuflen=<optimized out>) ... afp_over_dsi(obj=0x5555556154c0 <obj>).' 2.4.1 and 3.1.19 are also fixed versions.

Impact

For European organizations, the primary impact of CVE-2024-38440 is the potential disruption of AFP file sharing services due to denial of service caused by the heap overflow and subsequent segmentation fault. Organizations relying on Netatalk for network-attached storage, legacy file sharing, or integration with Apple devices may experience service outages, affecting business continuity and productivity. Critical sectors such as government, finance, education, and healthcare that utilize Unix-based file servers could face operational interruptions. Although no known remote code execution exploits exist yet, the heap corruption could be a stepping stone for more advanced attacks if combined with other vulnerabilities. The vulnerability's network accessibility and lack of authentication requirements increase the risk of exploitation by remote attackers. Given the widespread use of Unix/Linux systems in Europe and the presence of legacy AFP services, the threat is relevant, especially in environments where patching cycles are slow or where Netatalk is embedded in specialized appliances.

Summary

CVE-2024-38440 is a heap-based buffer overflow vulnerability identified in Netatalk, an open-source implementation of the Apple Filing Protocol (AFP) used primarily on Unix-like systems for file sharing. The vulnerability stems from an off-by-one error in the FPLoginExt operation, specifically within the BN_bin2bn function call in the uams_dhx_pam.c source file. The root cause is the lack of proper validation of the length field after parsing user-supplied data, which leads to writing a null byte out-of-bounds on the heap. This single-byte overflow can corrupt adjacent heap metadata, potentially triggering a segmentation fault and causing the AFP daemon (afpd) to crash. The issue affects Netatalk versions prior to 3.2.1, with fixed versions including 2.4.1 and 3.1.19. The vulnerability does not require any privileges or user interaction to exploit, as it can be triggered remotely by sending crafted AFP login extension requests. While the primary impact is denial of service, the heap corruption could theoretically be leveraged for more severe attacks, though no such exploits are currently known. The CVSS v3.1 base score of 7.5 reflects a high severity due to network attack vector, low attack complexity, no privileges required, no user interaction, and impact limited to availability. The vulnerability is tracked under CWE-193 (Off-by-one Error).

CWE-193Off-by-one Error (opens in a new tab)
Base weakness
A product calculates or uses an incorrect maximum or minimum value that is 1 more, or 1 less, than the correct value.
Implementation
When copying character arrays or using character manipulation methods, the correct size parameter must be used to account for the null terminator that needs to be added at the end of the array.
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 4 Nov 2025, 00:04 UTC

WeaknessesCWE-193

Technical details

References

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