CVE-2018-5382 — bcprov-jdk15on
MEDIUMCVE-2018-5382 is a medium-severity (CVSS 4.4) Broken Cryptographic Algorithm vulnerability in org.bouncycastle:bcprov-jdk15on. A fix is available for org.bouncycastle:bcprov-jdk15on — see the affected versions and patch details below.
Improper Validation of Integrity Check Value in Bouncy Castle
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-2018-5382 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 377,636 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
org.bouncycastle:bcprov-jdk15onReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.
Description
The default BKS keystore use an HMAC that is only 16 bits long, which can allow an attacker to compromise the integrity of a BKS keystore. Bouncy Castle release 1.47 changes the BKS format to a format which uses a 160 bit HMAC instead. This applies to any BKS keystore generated prior to BC 1.47. For situations where people need to create the files for legacy reasons a specific keystore type "BKS-V1" was introduced in 1.49. It should be noted that the use of "BKS-V1" is discouraged by the library authors and should only be used where it is otherwise safe to do so, as in where the use of a 16 bit checksum for the file integrity check is not going to cause a security issue in itself.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | org.bouncycastle:bcprov-jdk15on | all versions | 1.50org.bouncycastle:bcprov-jdk15on:1.50 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.bouncycastle:bcprov-jdk15on, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update org.bouncycastle:bcprov-jdk15on to 1.50 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2018-5382 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-2018-5382 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2018-5382. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
Red Hat Product Security has rated this issue as having a security impact of Low. This issue is not currently planned to be addressed in future updates. For additional information, refer to the Issue Severity Classification: https://access.redhat.com/security/updates/classification/.
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat Satellite 6.4 for RHEL 7 | ansiblerole-insights-client-0:1.5-1.el7sat | RHSA-2018:2927 |
Frequently Asked Questions
Is CVE-2018-5382 in your dependencies?
O3 Security finds CVE-2018-5382 across Maven dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.