Vulnerability in Rclone
CVE-2026-79775
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.004 (29.0th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 29th percentile — 29.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.004 · change: +0.001
Affected products
Weakness classification (CWE)
References
- github.com/rclone/rclone/security/advisories/GHSA-6jcg-q3wp-x2f4 (vendor-advisory)
- www.vulncheck.com/advisories/rclone-archive-backend-squashfs-parser-denial-of-s… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-79775?
- CVE-2026-79775 is a medium-severity vulnerability in Rclone, classified under Improper Validation of Array Index. CVSS score: 6.5/10. Published 2026-08-25.
- How severe is CVE-2026-79775?
- Medium severity. CVSS v3 base score is 6.5 out of 10.