What is CVE-2026-5588?

CVE-2026-5588 is a medium-severity use of a broken or risky cryptographic algorithm vulnerability in org.bouncycastle:bcpkix-jdk18on (maven), affecting versions >= 1.49, < 1.84. It is fixed in 1.84. The application uses a cryptographic algorithm known to have weaknesses, such as MD5, SHA-1, or DES.

Which packages are affected by CVE-2026-5588?

org.bouncycastle:bcpkix-jdk18on (maven) versions >= 1.49, = 1.49, = 1.49, = 1.49, = 1.49, = 1.49, = 1.49, < 1.84.

Is there a fix for CVE-2026-5588?

Yes. CVE-2026-5588 is fixed in 1.84. Upgrade to this version or later.

Is CVE-2026-5588 exploitable, and should I be worried?

Whether CVE-2026-5588 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk.

What actually determines whether CVE-2026-5588 is exploitable, and how bad it is?

Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.

CVE-2026-5588 in org.bouncycastle:bcpkix-jdk18on

Q: Which packages are affected by CVE-2026-5588?

org.bouncycastle:bcpkix-jdk18on (maven) versions >= 1.49, = 1.49, = 1.49, = 1.49, = 1.49, = 1.49, = 1.49, < 1.84.

Q: Is there a fix for CVE-2026-5588?

Yes. CVE-2026-5588 is fixed in 1.84. Upgrade to this version or later.

Q: Is CVE-2026-5588 exploitable, and should I be worried?

Whether CVE-2026-5588 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk.

Q: What actually determines whether CVE-2026-5588 is exploitable, and how bad it is?

Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.

Q: How do I fix CVE-2026-5588?

Upgrade: org.bouncycastle:bcpkix-jdk18on to 1.84 or later, org.bouncycastle:bcpkix-jdk15to18 to 1.84 or later, org.bouncycastle:bcpkix-jdk15on to 1.84 or later, org.bouncycastle:bcpkix-jdk14 to 1.84 or later, org.bouncycastle:bcpkix-debug-jdk18on to 1.84 or later, org.bouncycastle:bcpkix-debug-jdk15to18 to 1.84 or later, org.bouncycastle:bcpkix-debug-jdk14 to 1.84 or later.

Summary

Bouncy Castle Crypto Package For Java: Use of a Broken or Risky Cryptographic Algorithm vulnerability in bcpkix modules

: Use of a Broken or Risky Cryptographic Algorithm vulnerability in Legion of the Bouncy Castle Inc. BC-JAVA bcpkix on all (pkix modules).

PKIX draft CompositeVerifier accepts empty signature sequence as valid.

This issue affects BC-JAVA: from 1.49 before 1.84.

Impact

The application uses a cryptographic algorithm known to have weaknesses, such as MD5, SHA-1, or DES. Typical impact: compromised confidentiality or integrity of protected data.

Affected versions

org.bouncycastle:bcpkix-jdk18on (>= 1.49, < 1.84) org.bouncycastle:bcpkix-jdk15to18 (>= 1.49, < 1.84) org.bouncycastle:bcpkix-jdk15on (>= 1.49, < 1.84) org.bouncycastle:bcpkix-jdk14 (>= 1.49, < 1.84) org.bouncycastle:bcpkix-debug-jdk18on (>= 1.49, < 1.84) org.bouncycastle:bcpkix-debug-jdk15to18 (>= 1.49, < 1.84) org.bouncycastle:bcpkix-debug-jdk14 (>= 1.49, < 1.84)

Security releases

org.bouncycastle:bcpkix-jdk18on → 1.84 (maven) org.bouncycastle:bcpkix-jdk15to18 → 1.84 (maven) org.bouncycastle:bcpkix-jdk15on → 1.84 (maven) org.bouncycastle:bcpkix-jdk14 → 1.84 (maven) org.bouncycastle:bcpkix-debug-jdk18on → 1.84 (maven) org.bouncycastle:bcpkix-debug-jdk15to18 → 1.84 (maven) org.bouncycastle:bcpkix-debug-jdk14 → 1.84 (maven)

Kodem intelligence

Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.

Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.

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Remediation advice

Upgrade the following packages to resolve this vulnerability:

org.bouncycastle:bcpkix-jdk18on to 1.84 or later; org.bouncycastle:bcpkix-jdk15to18 to 1.84 or later; org.bouncycastle:bcpkix-jdk15on to 1.84 or later; org.bouncycastle:bcpkix-jdk14 to 1.84 or later; org.bouncycastle:bcpkix-debug-jdk18on to 1.84 or later; org.bouncycastle:bcpkix-debug-jdk15to18 to 1.84 or later; org.bouncycastle:bcpkix-debug-jdk14 to 1.84 or later

Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.

Frequently Asked Questions

What is CVE-2026-5588? CVE-2026-5588 is a medium-severity use of a broken or risky cryptographic algorithm vulnerability in org.bouncycastle:bcpkix-jdk18on (maven), affecting versions >= 1.49, < 1.84. It is fixed in 1.84. The application uses a cryptographic algorithm known to have weaknesses, such as MD5, SHA-1, or DES.
Which packages are affected by CVE-2026-5588?
- org.bouncycastle:bcpkix-jdk18on (maven) (versions >= 1.49, < 1.84)
- org.bouncycastle:bcpkix-jdk15to18 (maven) (versions >= 1.49, < 1.84)
- org.bouncycastle:bcpkix-jdk15on (maven) (versions >= 1.49, < 1.84)
- org.bouncycastle:bcpkix-jdk14 (maven) (versions >= 1.49, < 1.84)
- org.bouncycastle:bcpkix-debug-jdk18on (maven) (versions >= 1.49, < 1.84)
- org.bouncycastle:bcpkix-debug-jdk15to18 (maven) (versions >= 1.49, < 1.84)
- org.bouncycastle:bcpkix-debug-jdk14 (maven) (versions >= 1.49, < 1.84)
Is there a fix for CVE-2026-5588? Yes. CVE-2026-5588 is fixed in 1.84. Upgrade to this version or later.
Is CVE-2026-5588 exploitable, and should I be worried? Whether CVE-2026-5588 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
What actually determines whether CVE-2026-5588 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
How do I fix CVE-2026-5588?
- Upgrade org.bouncycastle:bcpkix-jdk18on to 1.84 or later
- Upgrade org.bouncycastle:bcpkix-jdk15to18 to 1.84 or later
- Upgrade org.bouncycastle:bcpkix-jdk15on to 1.84 or later
- Upgrade org.bouncycastle:bcpkix-jdk14 to 1.84 or later
- Upgrade org.bouncycastle:bcpkix-debug-jdk18on to 1.84 or later
- Upgrade org.bouncycastle:bcpkix-debug-jdk15to18 to 1.84 or later
- Upgrade org.bouncycastle:bcpkix-debug-jdk14 to 1.84 or later

Other vulnerabilities in org.bouncycastle:bcpkix-jdk18on

CVE-IDSeverityPackage summary

CVE-2025-8916Mediumorg.bouncycastle:bcpkix-fips: Bouncy Castle for Java bcpkix, bcprov, bcpkix-fips on All (API modules) allows Excessive Allocation CVE-2023-33202Mediumorg.bouncycastle:bcprov-jdk18on: Bouncy Castle Denial of Service (DoS)