CVE-2020-15128 is a medium-severity (CVSS 6.3) CWE-565 vulnerability in october/rain. A fix is available for october/rain — see the affected versions and patch details below.
Reliance on Cookies without validation in OctoberCMS
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2020-15128 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 376,715 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
october/rainReal-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
In OctoberCMS before version 1.0.468, encrypted cookie values were not tied to the name of the cookie the value belonged to. This meant that certain classes of attacks that took advantage of other theoretical vulnerabilities in user facing code (nothing exploitable in the core project itself) had a higher chance of succeeding. Specifically, if your usage exposed a way for users to provide unfiltered user input and have it returned to them as an encrypted cookie (ex. storing a user provided search query in a cookie) they could then use the generated cookie in place of other more tightly controlled cookies; or if your usage exposed the plaintext version of an encrypted cookie at any point to the user they could theoretically provide encrypted content from your application back to it as an encrypted cookie and force the framework to decrypt it for them. Issue has been fixed in build 468 (v1.0.468).
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | october/rain | ≥ 1.0.319&&< 1.0.468 | 1.0.468composer require october/rain:^1.0.468 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for october/rain, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update october/rain to 1.0.468 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-15128 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.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2020-15128 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2020-15128. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2020-15128 in your dependencies?
O3 Security finds CVE-2020-15128 across Packagist dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.