CVE intelligence and bounded remediation
CVE-2021-20876 — Groupsession Groupsession security vulnerability
Path traversal vulnerability in GroupSession Free edition ver5.1.1 and earlier, GroupSession byCloud ver5.1.1 and earlier, and GroupSession ZION ver5.1.1 and earlier allows an attacker with an administrative privilege to obtain sensitive information stored in the hierarchy above the directory on the published site's server via unspecified vectors.
- Severity
- Medium
- CVSS
- 6.8 (3.1)
- Published
- 2021-12-24
- CISA KEV
- Not currently listed
- Ecosystem
- software/application
- Weaknesses
- CWE-22
Affected products
- groupsession / groupsession
Showing 1 representative product identities from 3 source matches. Confirm exact affected versions with the linked vendor and NVD evidence.
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
The detailed catalog view below loads this exact record, its source evidence, and the full seven-phase agentic change plan.