Vulnerability · Published Feb 27, 2026 · Assigned by GitHub_M

CVE-2026-27734Beszel Vulnerable to Docker API Path Traversal via Unsanitized Container ID

Medium 6.5

In plain English

A medium-severity path traversal in beszel from henrygd. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 46% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)6.5Medium

Exploit odds (30 days)0.5%top 54.1% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official 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 packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Alpine:v3.23	beszel	0.18.7-r0	ALPINE-CVE-2026-27734
Go	github.com/henrygd/beszel	0.18.4	GHSA-phwh-4f42-gwf3
Go	github.com/henrygd/beszel	0.18.4	GO-2026-4571

Affected products (as reported)

Vendor	Product	Versions
henrygd	beszel	< 0.18.4

Weakness: CWE-22 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

References

https://github.com/henrygd/beszel/security/advisories/GHSA-phwh-4f42-gwf3 x_refsource_CONFIRM
https://github.com/henrygd/beszel/releases/tag/v0.18.4 x_refsource_MISC