# 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.

- **Severity:** High 7.1 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 25 Aug 2026
- **Updated:** 29 Aug 2026
- **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, UBUNTU-CVE-2026-79775

## 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 (Improper Validation of Array Index)

## Which versions are affected by CVE-2026-79775?

1 open source package ship an affected version, including rclone.


| Package | Ecosystem | 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.

## Is CVE-2026-79775 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-79775 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-79775 and fix it if it is affected.

What it is: 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.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-79775 exists.

Affected packages and fixed versions:
- rclone (Bitnami): affected from 1.72.0; fixed in 1.75.0

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-79775/ (Markdown: https://insights.sbomify.com/CVE-2026-79775/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-79775
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-79775
- OSV: https://osv.dev/vulnerability/CVE-2026-79775

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-79775/
Summaries are generated and may contain mistakes; the official description above is the record.