CVE-2015-8314 is a high-severity (CVSS 7.5) CWE-312 vulnerability in devise. A fix is available for devise — see the affected versions and patch details below.
Devise Gem for Ruby Unauthorized Access Using "Remember Me" Cookie
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.
- 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-2015-8314.
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
deviseReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects RubyGems packages — download data is not available via public APIs for these ecosystems.
Description
Devise version before 3.5.4 uses cookies to implement a "Remember me" functionality. However, it generates the same cookie for all devices. If an attacker manages to steal a remember me cookie and the user does not change the password frequently, the cookie can be used to gain access to the application indefinitely.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 💎RubyGems | devise | all versions | 3.5.4bundle update devise --conservative |
Affected Products
deviseheartcomboDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for devise, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update devise to 3.5.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2015-8314 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-2015-8314 in your dependencies?
Find it across RubyGems, including transitive dependencies.