# CVE-2026-57856 — Cockpit CMS

> As of 2026-07-14, CVE-2026-57856 is a HIGH-severity vulnerability in Cockpit CMS, CVSS v3.1 8.8, EPSS 0.3% (31.0th percentile). No Threadlinqs-tracked threat campaign has been attributed to CVE-2026-57856 as of 2026-07-14; the identifier is re-checked against the Threadlinqs threat corpus on every daily ingest.

**Last updated:** 2026-07-14

## What is CVE-2026-57856?

Cockpit CMS contains a path traversal vulnerability in the Bucket file storage API (/system/buckets/api). The api() method in modules/System/Controller/Buckets.php sanitizes the bucket name with preg_replace('/[^a-zA-Z0-9-_\\.]/','', $bucket), which permits '..' and '../' sequences. The sanitized value is interpolated into a Flysystem path as uploads://buckets/{bucket}. Flysystem's WhitespacePathNormalizer resolves 'buckets/..' to the empty string (the uploads storage root) without raising PathTraversalDetected because the '..' has a preceding component to consume. An authenticated low-privileged user can send a crafted request with a '../' bucket name to list, upload, and delete files across all buckets, including those belonging to other users or roles

The record classifies CVE-2026-57856 under weakness class [CWE-22](https://intel.threadlinqs.com/cwe/CWE-22). Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs low-privilege credentials, needs no user interaction, and has high impact on confidentiality, integrity, availability. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 84 days ago.

## Severity and exploitation probability

- **CVSS v3.1 base score:** 8.8 — HIGH (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **CVSS v4.0 base score:** 8.7 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`)
- **EPSS (FIRST):** 0.3% probability of exploitation in the next 30 days, higher than 31.0% of all scored CVEs
- **CISA KEV:** Not listed in the CISA Known Exploited Vulnerabilities catalog
- **Threadlinqs priority:** 5.6/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- **Published:** 2026-07-13, last modified 2026-07-14

## Is CVE-2026-57856 being exploited?

It currently carries a trending score of 37 in the Threadlinqs vulnerability feed.

## Affected products and versions

- **Cockpit HQ**: Cockpit CMS

## How to fix CVE-2026-57856

No vendor patch reference has been recorded for CVE-2026-57856 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.

## Threat activity tracking CVE-2026-57856

No threat campaign in the Threadlinqs corpus currently references CVE-2026-57856, in its CVE list or as an indicator. The linkage is recomputed from the live corpus on every daily ingest, so this section fills in as soon as a tracked campaign cites the identifier.

## Sources

Enriched from CVE.org, FIRST EPSS, GitHub Security Advisories, NVD. Last verified by Threadlinqs on 2026-07-15. This product uses the NVD API but is not endorsed or certified by the NVD.

**Vendor advisory and patch**

- [github.com — patch](https://github.com/Cockpit-HQ/Cockpit/commit/dde2d1d74f5f4e11de42a298918ea8c9684f932c)

**Technical analysis**

- [gist.github.com — technical description](https://gist.github.com/sermikr0/821c4edd3c34e98a62a50b07707785bd)

**Third-party advisory**

- [vulncheck.com — third party advisory](https://www.vulncheck.com/advisories/cockpit-cms-missing-authorization-in-bucket-file-storage-api)
- [vulncheck.com — third party advisory (cockpit cms path traversal via bucket na)](https://www.vulncheck.com/advisories/cockpit-cms-path-traversal-via-bucket-name-in-bucket-file-storage-api)

**Issue tracking and product pages**

- [github.com — product](https://github.com/cockpit-hq/cockpit)

Canonical: https://intel.threadlinqs.com/cve/CVE-2026-57856
Full detection coverage and IOCs for threats exploiting CVE-2026-57856 via the Threadlinqs MCP server (Purple tier): https://intel.threadlinqs.com/mcp