CVE intelligence and bounded remediation

CVE-2021-20197 — Gnu Binutils security vulnerability

Medium CVSS 6.3

There is an open race window when writing output in the following utilities in GNU binutils version 2.35 and earlier:ar, objcopy, strip, ranlib. When these utilities are run as a privileged user (presumably as part of a script updating binaries across different users), an unprivileged user can trick these utilities into getting ownership of arbitrary files through a symlink.

Severity
Medium
CVSS
6.3 (3.1)
Published
2021-03-26
CISA KEV
Not currently listed
Ecosystem
software/application
Weaknesses
CWE-59, CWE-362

Affected products

  • gnu / binutils
  • redhat / enterprise_linux / 8.0
  • netapp / cloud_backup
  • netapp / ontap_select_deploy_administration_utility
  • netapp / solidfire_&_hci_management_node
  • broadcom / brocade_fabric_operating_system_firmware

Matched remediation archetype

Path traversal, unsafe upload, and file handling

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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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