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CVE-2026-20358 – Unauthorized File System Access – Cisco Crosswork Planning, Crosswork Network Contr

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Summary

CVE-2026-20358 is a critical file-system-control vulnerability (CWE-73, External Control of File Name or Path) affecting Cisco Crosswork Planning, Cisco Crosswork Network Controller, and Cisco Crosswork Data Gateway. The flaw allows unauthorized access to the file system on affected devices and was discovered internally by Cisco during a comprehensive security review of the Crosswork product line. It carries the maximum CVSS v3.1 base score of 10.0, reflecting unauthenticated, network-exploitable, high-impact risk.

Technical details

  • Root cause: The affected software fails to properly validate or restrict externally supplied file names or paths, allowing an attacker to control which files on the underlying file system are accessed or manipulated (CWE-73).
  • Trigger conditions: No authentication or user interaction is required; an attacker only needs network reachability to the affected Crosswork component to exploit the flaw.
  • Attack vector: Network (AV:N), with low attack complexity (AC:L) and no privileges required (PR:N) or user interaction (UI:N).
  • Impact: The scope is changed (S:C), and successful exploitation results in high integrity and high availability impact, allowing an attacker to affect data and system operations, though the vulnerability does not directly impact confidentiality (C:N).
  • Disclosure context: This CVE was published alongside three related critical/high-severity Crosswork hardening issues (CVE-2026-20030, CVE-2026-20357, CVE-2026-20359) as part of Cisco’s August 19, 2026 Crosswork security hardening release. Cisco PSIRT states it is not aware of any public announcements or malicious use of this vulnerability.

Affected software

  • Cisco Crosswork Planning — versions 7.0.0 through 7.2.1 and earlier (including 7.0.0–7.0.4, 7.1.0–7.1.2, and 7.2.0–7.2.1)
  • Cisco Crosswork Network Controller — versions 7.2.1 and earlier
  • Cisco Crosswork Data Gateway — versions 7.2.1 and earlier

Severity

  • CVSS v3.1 Base Score: 10.0 (Critical)
  • Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:H

Mitigation and recommended actions

  • Immediate: Upgrade affected Crosswork Planning, Crosswork Network Controller, and Crosswork Data Gateway deployments to the fixed release, 7.2.1-SP, as specified in Cisco’s security advisory.
  • If immediate patching is not possible: Cisco states there are no workarounds that address this vulnerability. Organizations that cannot patch immediately should restrict network access to Crosswork management interfaces to trusted administrative networks only, and monitor for anomalous file access or system behavior on affected hosts until the fix can be applied.

References

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