CVE-2021-3980 is a high-severity (CVSS 7.5) CWE-359 vulnerability in elgg/elgg. 1 public exploit or proof-of-concept reference is indexed, so weaponization risk is real. A fix is available for elgg/elgg — see the affected versions and patch details below.
Information exposure in elgg
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
elgg/elgg🐘elgg/elggReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.
Description
elgg is vulnerable to Exposure of Private Personal Information to an Unauthorized Actor. Forms in the view namespace 'forms/admin' were not protected by an AdminGatekeeper in case of AJAX requests to 'ajax/form/admin/'.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | elgg/elgg | all versions | 3.3.23composer require elgg/elgg:^3.3.23 |
| 🐘Packagist | elgg/elgg | ≥ 4.0.0&&< 4.0.5 | 4.0.5composer require elgg/elgg:^4.0.5 |
Affected Products
elggelggResearch use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for elgg/elgg, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update elgg/elgg to 3.3.23 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-3980 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
Frequently Asked Questions
Is CVE-2021-3980 in your dependencies?
Find it across Packagist, including transitive dependencies.