CVE intelligence and bounded remediation

CVE-2020-35951 — An issue was discovered in the Quiz and Survey Master plugin before 7.0.1 for WordPress

Critical CVSS 9.9

An issue was discovered in the Quiz and Survey Master plugin before 7.0.1 for WordPress. It allows users to delete arbitrary files such as wp-config.php file, which could effectively take a site offline and allow an attacker to reinstall with a WordPress instance under their control. This occurred via qsm_remove_file_fd_question, which allowed unauthenticated deletions (even though it was only intended for a person to delete their own quiz-answer files).

Severity
Critical
CVSS
9.9 (3.1)
Published
2021-01-01
CISA KEV
Not currently listed
Ecosystem
php/wordpress
Weaknesses
CWE-306

Affected products

  • expresstech / quiz_and_survey_master

Matched remediation archetype

Authentication bypass and missing authentication

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

Check exposure

  • Map every affected endpoint and protocol path, including alternate ports, legacy routes, recovery flows, service accounts, and machine-to-machine access.
  • Confirm which deployments enable the affected authentication mode and whether the interface is reachable from untrusted networks.
  • Review session, token, credential, and proxy trust configuration without attempting account takeover.

Remediate safely

  • Apply the supported fix and centralize fail-closed authentication before protected request handling.
  • Remove default or embedded credentials, rotate affected secrets and sessions, and bind authentication decisions to the intended audience and channel.
  • Add negative tests for alternate routes, malformed or absent credentials, recovery flows, and proxy-derived identity.

Authoritative sources

Complete CVE record and remediation plan

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