How severe is CVE-2026-27734?

CVE-2026-27734 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2026-27734 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (38th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-27734?

CVE-2026-27734 affects Beszel. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-27734?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-27734 have an EU (EUVD) identifier?

Yes. CVE-2026-27734 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-9053.

When was CVE-2026-27734 published?

CVE-2026-27734 was published on 2026-02-27 and last updated on 2026-06-17.

CVE-2026-27734

CVE-2026-27734 is a medium-severity vulnerability in Beszel with a CVSS 3.x base score of 6.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-22.

Key facts

Severity: Medium (CVSS 3.x base score 6.5)
EPSS exploit prediction: 0% (38th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-9053
Weakness: CWE-22
Affected product: Beszel
Published: 2026-02-27
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2026-27734?: 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.
How severe is CVE-2026-27734?: CVE-2026-27734 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2026-27734 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (38th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-27734?: CVE-2026-27734 affects Beszel. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-27734?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-27734 have an EU (EUVD) identifier?: Yes. CVE-2026-27734 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-9053.
When was CVE-2026-27734 published?: CVE-2026-27734 was published on 2026-02-27 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:beszel:beszel:*:*:*:*:*:*:*:*

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