CVE-2026-27734

Beszel Vulnerable to Docker API Path Traversal via Unsanitized Container ID

MEDIUM
6.5
CVSS Score
Published: February 27, 2026 at 07:41 PM UTC
Updated: June 17, 2026 at 10:27 AM UTC
2 products affected across 2 vendorsBeszelBeszel

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Severity
MEDIUM6.5
Exploit prediction
EPSS 0.5%
SSVC
No known exploit

Description

Beszel is a server monitoring platform. Prior to version 0.18.2, the hub's authenticated API endpoints GET /api/beszel/containers/logs and GET /api/beszel/containers/info pass the user-supplied "container" query parameter to the agent without validation. The agent constructs Docker Engine API URLs using fmt.Sprintf with the raw value instead of url.PathEscape(). Since Go's http.Client does not sanitize `../` sequences from URL paths sent over unix sockets, an authenticated user (including readonly role) can traverse to arbitrary Docker API endpoints on agent hosts, exposing sensitive infrastructure details. Version 0.18.4 fixes the issue.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 0.18.2
v < 0.18.4
Affected range stops below 0.18.4, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (2)

x_refsource_CONFIRMExploitVendor Advisory
Source: cverecord
https://github.com/henrygd/beszel/security/advisories/GHSA-phwh-4f42-gwf3
x_refsource_MISCProductRelease Notes
Source: cverecord
https://github.com/henrygd/beszel/releases/tag/v0.18.4

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

6.5MEDIUMGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
NONE
Availability
NONE
Vector?

Quick Info

StatusANALYZED
CWE
CWE-22

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