CVE-2023-33977 is a high-severity (CVSS 8.1) Cross-site Scripting (XSS) vulnerability in kiwitcms. 1 public exploit or proof-of-concept reference is indexed, so weaponization risk is real. A fix is available for kiwitcms — see the affected versions and patch details below.
Stored cross site scripting (XSS) via unrestricted file upload in Kiwi TCMS
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
- A successful exploit gives an attacker total control of the affected component, not partial access.
Exploitation and automatability from CISA’s SSVC triage for CVE-2023-33977.
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
kiwitcmsReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
Description
Kiwi TCMS is an open source test management system for both manual and automated testing. Kiwi TCMS allows users to upload attachments to test plans, test cases, etc. Earlier versions of Kiwi TCMS had introduced upload validators in order to prevent potentially dangerous files from being uploaded and Content-Security-Policy definition to prevent cross-site-scripting attacks. The upload validation checks were not 100% robust which left the possibility to circumvent them and upload a potentially dangerous file which allows execution of arbitrary JavaScript in the browser. Additionally we've discovered that Nginx's proxy_pass directive will strip some headers negating protections built into Kiwi TCMS when served behind a reverse proxy. This issue has been addressed in version 12.4. Users are advised to upgrade. Users unable to upgrade who are serving Kiwi TCMS behind a reverse proxy should make sure that additional header values are still passed to the client browser. If they aren't redefining them inside the proxy configuration.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | kiwitcms | all versions | 12.4pip install --upgrade 'kiwitcms==12.4' |
Affected Products
kiwi tcmskiwitcmsResearch 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 kiwitcms, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update kiwitcms to 12.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-33977 is resolved across your whole dependency graph.
Workarounds
Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.
Frequently Asked Questions
Is CVE-2023-33977 in your dependencies?
Find it across PyPI, including transitive dependencies.