Bug 2523581 (CVE-2026-79775)

Summary: CVE-2026-79775 github.com/diskfs/go-diskfs: rclone: Denial of Service via malicious SquashFS image parsing
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: aazores, akhatavk, aos-team-art-private, asdas, cmah, dpaolell, eaguilar, ebaron, gparvin, jdelft, jmatsuok, jtolenti, jupierce, lgamliel, lgarciaa, mbiarnes, pjindal, ppalepu, ppostler, prdhamdh, rhaigner, sbratsla, sghai, sidsharm, suppawar, vlaad
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in rclone. The archive backend's SquashFS parser fails to validate attacker-controlled superblock and metadata values before use. An attacker who can place or modify a malicious SquashFS image in storage exposed through an rclone :archive: remote can trigger multiple denial-of-service vulnerabilities. This can lead to an integer division-by-zero panic, an out-of-bounds slice panic, or a non-progress CPU loop, which can terminate the rclone process, potentially crash an SFTP server, or cause sustained CPU consumption.
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Description OSIDB Bzimport 2026-08-25 15:36:10 UTC 
rclone versions >= v1.72.0 and <= v1.74.4 (fixed in v1.75.0) contain multiple denial-of-service vulnerabilities in the archive backend's SquashFS parser, which relies on the github.com/diskfs/go-diskfs dependency. The parser fails to validate attacker-controlled superblock and metadata values before use. An attacker who can place or modify a SquashFS image in storage exposed through an rclone :archive: remote can craft a malicious image that triggers an integer division-by-zero panic (zero block size), an out-of-bounds slice panic (out-of-range inode metadata offset), or a non-progress CPU loop (truncated metadata stream). Variants 1 and 2 terminate the rclone process and, via 'rclone serve sftp', can crash the entire SFTP server; variant 3 causes sustained CPU consumption. Parsing is lazy, so a victim or remote client must address or descend into the malicious archive object to trigger it.