Security readout for executives and security teams
Plain-English summary
Beszel versions before 0.18.4 can let any authenticated user, including readonly users, use specific container API features to reach unintended Docker API paths on agent hosts. The main business risk is exposure of sensitive infrastructure information. Public sources do not indicate active exploitation.
Executive priority
Treat as a near-term remediation item, not an emergency based on current evidence. Prioritize upgrade where Beszel monitors production Docker hosts or where readonly access is broadly granted.
Technical view
The hub endpoints for container logs and info pass an unsanitized container query value to the agent. The agent builds Docker Engine API URLs with the raw value, allowing path traversal over the Docker unix socket. CVSS is 6.5 with high confidentiality impact, low complexity, and required low privileges.
Likely exposure
Organizations running henrygd Beszel before version 0.18.4 are potentially exposed, especially where non-admin or readonly users can authenticate to the Beszel hub. Exposure depends on deployed agent hosts and what Docker API information is reachable through the vulnerable paths.
Exploitation context
Exploitation requires valid Beszel authentication but no user interaction. The advisory states readonly users are sufficient. The reported impact is access to arbitrary Docker API endpoints on agent hosts, exposing sensitive infrastructure details. There is no KEV listing and no cited evidence of active exploitation.
Researcher notes
The source data has a minor wording tension: it describes behavior prior to 0.18.2 but lists affected versions as below 0.18.4 and states 0.18.4 fixes it. Use the advisory and release as authoritative for remediation.
Mitigation direction
- Upgrade Beszel to version 0.18.4 or later.
- Review vendor advisory and release notes for environment-specific guidance.
- Limit Beszel access to trusted users until upgraded.
- Reassess readonly accounts because they are included in the vulnerable access path.
Validation and detection
- Inventory Beszel hub and agent versions across environments.
- Confirm all deployments are running version 0.18.4 or later.
- Identify authenticated users with access to container logs or info features.
- Review Beszel access logs for unusual use of affected endpoints, if available.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-22: File access and web shell behavior lookup
File traversal and upload weaknesses can lead teams to review file, web shell, execution, and collection telemetry. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupFile access behavior lookup
The CVE wording references file access or upload behavior, so file telemetry and web shell review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupContainer behavior lookup
The affected technology mentions containers, so container-specific ATT&CK technique review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2026-27734 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Medium
- CVSS
- 6.5 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N2.83.6Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
6.5MediumVector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/henrygd/beszel/security/advisories/GHSA-phwh-4f42-gwf3CVE reference · x_refsource_CONFIRM
- https://github.com/henrygd/beszel/releases/tag/v0.18.4CVE reference · x_refsource_MISC
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.