CVE-2024-38440: Netatalk before 3.2.1 has an off-by-one error, and resultant heap-based buffer overflow and segmentation violation, because of incorrectly using FPLog...

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.

Metrics

CVSS 3.1

7.5/10

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

EPSS Probability

0.88%

54.5th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-193

Affected Software

Vendor	Product	Versions
Netatalk	Netatalk	>= 2.0.0, < 2.4.1
Netatalk	Netatalk	>= 3.0, < 3.1.19
Netatalk	Netatalk	3.2.0

References

https://github.com/Netatalk/netatalk/blob/90d91a9ac9a7d6132ab7620d31c8c23400949206/etc/uams/uams_dhx_pam.c#L199-L200Product
https://github.com/Netatalk/netatalk/issues/1097Not Applicable
https://github.com/Netatalk/netatalk/security/advisories/GHSA-mxx4-9fhm-r3w5Exploit, Vendor Advisory
https://netatalk.io/security/CVE-2024-38440Vendor Advisory
https://github.com/Netatalk/netatalk/blob/90d91a9ac9a7d6132ab7620d31c8c23400949206/etc/uams/uams_dhx_pam.c#L199-L200Product
https://github.com/Netatalk/netatalk/issues/1097Not Applicable
https://github.com/Netatalk/netatalk/security/advisories/GHSA-mxx4-9fhm-r3w5Exploit, Vendor Advisory
https://lists.debian.org/debian-lts-announce/2024/11/msg00026.html
https://netatalk.io/security/CVE-2024-38440Vendor Advisory

Timeline

Published: Jun 16, 2024
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2024-38440?

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.

How severe is CVE-2024-38440?

CVE-2024-38440 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 0.88% probability of exploitation in the next 30 days.

How do I fix CVE-2024-38440?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.