Netatalk has Integer Underflow → Stack Buffer Overflow in copydir()

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-45699
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-14 19:17:18 UTC
Updated2026-08-18 02:17:26 UTC
DescriptionNetatalk is a Free and Open Source file server suite for Unix-like operating systems. In versions 3.1.19 through 4.4.2, a stack-based buffer overflow exists in the copydir() function of Netatalk's afpd daemon due to an integer underflow in the calculation of the remaining buffer size used for path construction. copydir() is a utility function called when a file operation crosses a device boundary inside an AFP shared volume, which the standard library's renameat() cannot handle. The function attempts to track available buffer space using srem and drem for source and destination paths. Incorrect arithmetic causes both srem and drem to underflow to SIZE_MAX. Consequently, boundary checks against strlen(de->d_name) always pass, allowing strcpy() to append filenames into nearly full stack buffers. Version 4.4.3 patches the issue. As a workaround, configure each AFP shared volume to be structured as a single file system, in other words no subdirectory of a shared volume should be a mount point for a different file system.

Risk And Classification

Primary CVSS: v3.1 7.5 HIGH from [email protected]

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

EPSS: 0.003350000 probability, percentile 0.263990000 (date 2026-08-18)

Problem Types: CWE-191 | CWE-191 CWE-191: Integer Underflow (Wrap or Wraparound)

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary7.5HIGHCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
3.1CNADECLARED7.5HIGHCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS v3.1 Breakdown

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

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Netatalk Netatalk affected >= 3.1.19, < 4.4.3 Not specified

References

ReferenceSourceLinkTags
github.com/Netatalk/netatalk/security/advisories/GHSA-fphv-pf29-p77m [email protected] github.com
github.com/Netatalk/netatalk/releases/tag/netatalk-4-4-3 [email protected] github.com
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