CVE-2026-54578 in mport
Summary
by MITRE • 09/17/2026
mport is the MidnightBSD Package Manager. Prior to 2.7.8, mport_verify_package() in libmport/verify.c could continue after MD5File() or SHA256_File() failed and compare an expected checksum with stale data in the hash buffer rather than a newly computed digest. An attacker able to influence an installed file or the conditions that make hashing fail could receive a misleading integrity result or hide a checksum failure. This issue is fixed in version 2.7.8.
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Analysis
by VulDB Data Team • 09/17/2026
The MidnightBSD Package Manager, known as mport, serves as a critical infrastructure component for software distribution and system maintenance within the MidnightBSD operating environment. A significant security flaw was identified in versions prior to 2.7.8 regarding the integrity verification process during package installation or update operations. Specifically, the function mport_verify_package located in libmport/verify.c exhibited improper error handling when computing cryptographic hashes for file validation. This vulnerability stems from a failure to properly check return codes and handle execution flow deviations resulting from hashing failures, leading to potential bypasses of integrity checks that are fundamental to secure software deployment practices.
The technical root cause involves the behavior of the MD5File or SHA256_File functions when they encounter errors such as file not found, permission denied, or I/O issues. Instead of aborting the verification process and reporting a failure, the code continued execution with uninitialized or stale data remaining in the hash buffer from previous operations. Consequently, the system would compare an expected checksum against this invalid digest rather than computing and comparing it against the actual current content of the file. This logic error means that if an attacker can influence the conditions under which hashing fails—such as by manipulating file permissions, introducing race conditions, or altering filesystem states—the integrity check may erroneously report success even when the file has been tampered with or is corrupted.
From a security architecture perspective, this flaw represents a classic case of improper input validation and error handling leading to authentication bypass in the context of software supply chain integrity. The vulnerability aligns closely with CWE-253, which describes incorrect check for condition before action, as well as CWE-798, involving the use of hardcoded or default credentials where here it translates to relying on stale state data instead of fresh computation. In terms of offensive security frameworks, this could be leveraged within MITRE ATT&CK technique T1608, specifically related to Spearphishing Attachment if combined with social engineering, but more directly relates to T1574 Hijack Execution Flow or T1203 Exploitation for Client Execution by ensuring that malicious payloads are accepted as valid packages. The core issue is a lack of strict adherence to fail-secure principles where any deviation in the hashing process should result in an immediate rejection rather than a fallback to potentially misleading results.
The operational impact of this vulnerability allows for potential compromise of system integrity through the installation of modified or malicious software packages that appear legitimate due to false positive verification results. An attacker with local access who can manipulate file attributes or trigger hash computation errors could inject backdoors, trojans, or other malware into the package repository cache or installed binaries without detection by standard update mechanisms. This undermines trust in the package management system and exposes users to remote code execution risks if subsequent exploitation of the injected malicious software is possible. It also poses a risk for organizations relying on automated patching systems that assume verified packages are untampered, potentially leading to widespread compromise across managed endpoints.
Mitigation strategies primarily involve upgrading mport to version 2.7.8 or later where this logic error has been corrected to ensure proper termination of the verification process upon any hashing failure. Until an upgrade is feasible, administrators should implement additional controls such as strict file permission auditing to prevent unauthorized modification of package files and monitor for anomalies in hash computation logs if available. Furthermore, adopting a defense-in-depth approach by verifying digital signatures alongside checksums can provide an extra layer of assurance against tampering. Security teams should also review their software supply chain processes to ensure that no single point of failure like this flawed integrity check remains unmitigated across critical infrastructure components. Regular audits and penetration testing focusing on package manager interactions with the filesystem are recommended to identify similar logic flaws in other system utilities.