CVE-2021-26642 — xpressengine
CRITICALCVE-2021-26642 is a critical-severity (CVSS 9.8) Unrestricted File Upload vulnerability in xpressengine/xpressengine. A fix is available for xpressengine/xpressengine — see the affected versions and patch details below.
XpressEngine vulnerable to Unrestricted Upload of File with Dangerous Type
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- A successful exploit gives an attacker total control of the affected component, not partial access.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2021-26642.
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
xpressengine/xpressengineReal-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
When uploading an image file to a bulletin board developed with XpressEngine, a vulnerability in which an arbitrary file can be uploaded due to insufficient verification of the file. A remote attacker can use this vulnerability to execute arbitrary code on the server where the bulletin board is running.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | xpressengine/xpressengine | all versions | 3.0.15composer require xpressengine/xpressengine:^3.0.15 |
Affected Products
xpressenginexpressengineDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for xpressengine/xpressengine, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update xpressengine/xpressengine to 3.0.15 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-26642 is resolved across your whole dependency graph.
Workarounds
Treat uploaded files as untrusted until proven otherwise: validate the actual content type rather than the supplied extension, store uploads outside the web root on a volume mounted without execute permission, and rename them to server-generated identifiers so an attacker cannot choose the path a request will later resolve.
Frequently Asked Questions
Is CVE-2021-26642 in your dependencies?
Find it across Packagist, including transitive dependencies.