CVE intelligence and bounded remediation

CVE-2020-26820 — Sap Netweaver Application Server Java security vulnerability

Critical CVSS 9.1

SAP NetWeaver AS JAVA, versions - 7.20, 7.30, 7.31, 7.40, 7.50, allows an attacker who is authenticated as an administrator to use the administrator console, to expose unauthenticated access to the file system and upload a malicious file. The attacker or another user can then use a separate mechanism to execute OS commands through the uploaded file leading to Privilege Escalation and completely compromise the confidentiality, integrity and availability of the server operating system and any application running on it.

Severity
Critical
CVSS
9.1 (3.0)
Published
2020-11-10
CISA KEV
Not currently listed
Ecosystem
java/maven
Weaknesses
CWE-434

Affected products

  • sap / netweaver_application_server_java / 7.20
  • sap / netweaver_application_server_java / 7.30
  • sap / netweaver_application_server_java / 7.31
  • sap / netweaver_application_server_java / 7.40
  • sap / netweaver_application_server_java / 7.50

Matched remediation archetype

Path traversal, unsafe upload, and file handling

This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.

Check exposure

  • Trace untrusted filenames, archive entries, URLs, and path segments into read, write, include, extraction, and upload operations.
  • Identify filesystem roots, mount permissions, symbolic-link behavior, archive handling, and whether uploaded content is web-accessible or executable.
  • Review canonicalization and containment checks across supported operating systems and storage backends.

Remediate safely

  • Generate server-side storage identifiers and resolve paths beneath a fixed root using filesystem-aware containment checks.
  • Reject absolute, parent-relative, alternate-separator, device, link, and archive entries that escape the intended root.
  • Store uploads outside executable or served paths, validate type and size, and use private atomic temporary files.

Authoritative sources

Complete CVE record and remediation plan

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