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PatchSiren cyber security CVE debrief

CVE-2026-9397 Besen CVE debrief

A high-severity improper authorization vulnerability affects Besen BS20 EV Charging Station firmware versions up to 20260426. The weakness resides in the OTA Update Installation Handler component, where insufficient authorization checks may allow remote attackers to install unauthorized firmware updates. The attack requires high complexity and is considered difficult to exploit. The vulnerability was disclosed to Besen in April 2026, with vendor acknowledgment of ongoing review. No known exploitation in the wild or ransomware campaign use has been reported.

Vendor
Besen
Product
BS20 EV Charging Station
CVSS
HIGH 8.2
CISA KEV
Not listed in stored evidence
Original CVE published
2026-05-24
Original CVE updated
2026-07-23
Advisory published
2026-05-24
Advisory updated
2026-07-23

Who should care

Organizations operating Besen BS20 EV Charging Stations, critical infrastructure operators with EV charging deployments, IoT/OT security teams, and facilities management responsible for EV charging infrastructure security.

Technical summary

The Besen BS20 EV Charging Station's OTA Update Installation Handler fails to properly validate authorization for firmware installation operations. A remote attacker with sufficient technical capability could potentially bypass authorization checks to install malicious or unauthorized firmware, resulting in complete compromise of confidentiality, integrity, and availability of the charging station. The attack complexity is high due to required conditions, and exploitation is considered difficult. The vulnerability affects all firmware versions up to and including 20260426.

Defensive priority

HIGH

Recommended defensive actions

  • Verify Besen BS20 EV Charging Station firmware version and ensure updates beyond 20260426 are installed when available
  • Implement network segmentation to restrict EV charging station management interfaces from untrusted networks
  • Monitor for unauthorized OTA update attempts through network traffic analysis and device integrity checks
  • Contact Besen for official security advisory and patch timeline
  • Review and strengthen OTA update signing and verification mechanisms for IoT/OT device deployments

Evidence notes

CVSS 4.0 vector: AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P. CWE-266 (Incorrect Privilege Assignment) and CWE-285 (Improper Authorization) identified. VulnStatus: Deferred in NVD.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-9397 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-9397

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-9397 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-9397

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.