Bug 2517555 (CVE-2026-45698)

Summary: CVE-2026-45698 netatalk: Netatalk: Arbitrary code execution via stack-based buffer overflow in deletedir()
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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Priority: high    
Version: unspecifiedKeywords: Security
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OS: Linux   
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A flaw was found in Netatalk. A stack-based buffer overflow in the `deletedir()` function of the `afpd` daemon can be exploited by a remote attacker. This occurs due to an integer underflow during path construction, which allows attacker-controlled filenames to be copied into a stack buffer without proper bounds checking. This can lead to arbitrary code execution or a denial of service.
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Bug Depends On: 2521863, 2521864    
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Description OSIDB Bzimport 2026-08-17 18:57:05 UTC 
Netatalk 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 deletedir() function of Netatalk's afpd daemon due to an integer underflow in the calculation of the remaining buffer size used for path construction. deletedir() 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 prevent buffer overflows by tracking available space in a size_t remain variable. However, the arithmetic used to compute remain results in an unsigned integer underflow, causing the variable to become SIZE_MAX. Because of this, the subsequent boundary check always evaluates as safe, allowing an unbounded strcpy() operation to copy attacker-controlled filenames into a nearly full stack buffer. Version 4.4.3 patches the issue.