CVE-2026-79775 rclone Archive Backend SquashFS Parser Denial of Service
Attackers can crash rclone or its SFTP server by providing malicious SquashFS images, causing denial of service via parser errors.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-79775?
CVE-2026-79775 is a high-severity denial of service vulnerability in rclone, published on 25 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
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.
Weakness: CWE-129
Which versions are affected by CVE-2026-79775?
1 open source package ship an affected version, including rclone.
| Package | Affected | Fixed in |
|---|---|---|
rclone Bitnami | From 1.72.0 | 1.75.0 |
How do I fix CVE-2026-79775?
Upgrade rclone to 1.75.0 or later.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-79775 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-79775 exists.
Sources
Also known as BIT-rclone-2026-79775, DEBIAN-CVE-2026-79775, GHSA-6jcg-q3wp-x2f4, GHSA-hqq5-m7fp-mqc3, MINI-c4pw-vg4w-7g26, MINI-xfc9-gpwm-rfgm and 1 more.