CVE-2026-5598: Bouncy Castle Bouncy Castle Has Covert Timing Vulnerability

HIGH
Advisory Identifier: GHSA-p93r-85wp-75v3
CWE-385
Published
Advisory Summary

CVE-2026-5598 is a HIGH bouncy castle has covert timing vulnerability (CWE-385: Covert Timing Channel) affecting Bouncy Castle libraries in the Maven ecosystem. The issue involves bouncy castle has covert timing channel vulnerability. Remediation is available by upgrading affected packages to version 1.80.2, 1.81.1, 1.84.

CVE-2026-5598 at a Glance

CVE Identifier CVE-2026-5598
GHSA Identifier GHSA-p93r-85wp-75v3
Severity HIGH
CVSS v3.1 Base Score N/A
CWE Classification CWE-385: Covert Timing Channel
Affected Product Bouncy Castle
Package Ecosystem Maven
Published Date
Last Updated

How to Fix CVE-2026-5598

To remediate this vulnerability, upgrade all affected Bouncy Castle dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

org.bouncycastle:bcprov-jdk15to18 fixed: 1.80.2
<dependency>
    <groupId>org.bouncycastle</groupId>
    <artifactId>bcprov-jdk15to18</artifactId>
    <version>1.80.2</version>
</dependency>
org.bouncycastle:bcprov-jdk14 fixed: 1.81.1
<dependency>
    <groupId>org.bouncycastle</groupId>
    <artifactId>bcprov-jdk14</artifactId>
    <version>1.81.1</version>
</dependency>
org.bouncycastle:bcprov-jdk18on fixed: 1.84
<dependency>
    <groupId>org.bouncycastle</groupId>
    <artifactId>bcprov-jdk18on</artifactId>
    <version>1.84</version>
</dependency>
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release:

mvn dependency:tree -Dincludes=org.bouncycastle

How to Check if You Are Affected

To determine whether your Java application is affected by CVE-2026-5598, inspect your build dependencies using the Maven Dependency Plugin:

mvn dependency:tree -Dincludes=org.bouncycastle

Analyze the terminal output to locate any version of Bouncy Castle in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 1.80.2), your application is affected.

Note: The mvn dependency:tree -Dincludes=org.bouncycastle command inspects the resolved dependency graph declared in your project's POM files; it does not perform automated security scanning or inspect runtime dynamic classpaths. Always verify runtime container classpaths and shaded JARs.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-385: Covert Timing Channel, where covert timing channels convey information by modulating some aspect of system behavior over time, so that the program receiving the information can observe system behavior and infer protected information. In Bouncy Castle, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

Covert timing channel vulnerability in Legion of the Bouncy Castle Inc. BC-JAVA core on all (core modules). This vulnerability is associated with program files FrodoEngine.Java. This issue only affects users of the FrodoKEM algorithm involved in the decryption of encapsulations. This issue affects BC-JAVA: from 1.71 to 1.80.1, 1.81, 1.82 to 1.83. Fixed versions: 1.80.2, 1.81.1, 1.84

CVE-2026-5598 Affected Bouncy Castle Versions

3 component(s)
Fixed Versions:
1.80.21.81.11.84
Product / Package Ecosystem Affected Versions Fixed Version
org.bouncycastle:bcprov-jdk15to18
Maven
≥ 1.71
< 1.80.2
1.80.2
org.bouncycastle:bcprov-jdk14
Maven
≥ 1.81
< 1.81.1
1.81.1
org.bouncycastle:bcprov-jdk18on
Maven
≥ 1.82
< 1.84
1.84

References

Frequently Asked Questions

What is CVE-2026-5598?
CVE-2026-5598 is a security vulnerability in Bouncy Castle involving Bouncy Castle Has Covert Timing Channel Vulnerability under CWE-385: Covert Timing Channel.
Which Bouncy Castle versions are affected?
Affected versions include releases prior to 1.80.2, 1.81.1, 1.84 across affected packages: org.bouncycastle:bcprov-jdk15to18, org.bouncycastle:bcprov-jdk14, org.bouncycastle:bcprov-jdk18on.
What version fixes CVE-2026-5598?
Upgrading to 1.80.2, 1.81.1, 1.84 (or the latest patched release for your respective branch) resolves the vulnerability.
Is bcprov-jdk15to18 affected?
Yes, org.bouncycastle:bcprov-jdk15to18 is affected in releases prior to 1.80.2. Upgrade your dependency to 1.80.2 or later.
Is bcprov-jdk14 affected?
Yes, org.bouncycastle:bcprov-jdk14 is affected in releases prior to 1.81.1. Upgrade your dependency to 1.81.1 or later.
What CWE is associated with CVE-2026-5598?
CVE-2026-5598 is classified under CWE-385: Covert Timing Channel (Covert timing channels convey information by modulating some aspect of system behavior over time, so that the program receiving the information can observe system behavior and infer protected information.).
How can I check Maven dependencies for CVE-2026-5598?
Run the dependency tree command: 'mvn dependency:tree -Dincludes=org.bouncycastle'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-p93r-85wp-75v3",
  "modified" : "2026-06-19T15:20:41Z",
  "published" : "2026-04-17T18:31:50Z",
  "aliases" : [ "CVE-2026-5598" ],
  "summary" : "Bouncy Castle Has Covert Timing Channel Vulnerability",
  "details" : "Covert timing channel vulnerability in Legion of the Bouncy Castle Inc. BC-JAVA core on all (core modules). This vulnerability is associated with program files FrodoEngine.Java.\n\nThis issue only affects users of the FrodoKEM algorithm involved in the decryption of encapsulations.\n\nThis issue affects BC-JAVA: from 1.71 to 1.80.1, 1.81, 1.82 to 1.83.\n\nFixed versions: 1.80.2, 1.81.1, 1.84",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:H/SI:H/SA:N/E:U/S:P/AU:Y/U:Red"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "org.bouncycastle:bcprov-jdk15to18"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "1.71"
      }, {
        "fixed" : "1.80.2"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "org.bouncycastle:bcprov-jdk14"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "1.81"
      }, {
        "fixed" : "1.81.1"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "org.bouncycastle:bcprov-jdk18on"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "1.82"
      }, {
        "fixed" : "1.84"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-5598"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/bcgit/bc-java/commit/8692e6b2b191fc4aafa32545c7a78bdb9bf110c5"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/bcgit/bc-java/commit/94abbd56413dfdac651fd878bc60253871ef5e87"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/bcgit/bc-java"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/bcgit/bc-java/wiki/CVE%E2%80%902026%E2%80%905598"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/bcgit/bc-java/wiki/CVE-2026-5598"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-385" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-04-25T23:25:24Z",
    "nvd_published_at" : "2026-04-15T10:16:49Z"
  }
}