CVE-2026-5598 Non-constant time comparisons risk private key leakage in FrodoKEM.
High 8.9
Published
Updated
Check this codebase for CVE-2026-5598 and fix it if it is affected.
What it is: CVE-2026-5598 is a high-severity vulnerability in Legion of the Bouncy Castle Inc. BC-JAVA, published on 15 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-5598 in the wild and no public exploit code.
Affected packages and fixed versions:
- org.bouncycastle:bcprov-jdk14 (Maven): affected from 1.81; fixed in 1.81.1
- org.bouncycastle:bcprov-jdk14 (Maven): affected from 1.81; fixed in 1.81.1
- org.bouncycastle:bcprov-jdk15to18 (Maven): affected from 1.71; fixed in 1.80.2
- org.bouncycastle:bcprov-jdk15to18 (Maven): affected from 1.71; fixed in 1.80.2
- org.bouncycastle:bcprov-jdk18on (Maven): affected from 1.82; fixed in 1.84
- org.bouncycastle:bcprov-jdk18on (Maven): affected from 1.82; fixed in 1.84
Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.
Reference: https://insights.sbomify.com/CVE-2026-5598/ (Markdown: https://insights.sbomify.com/CVE-2026-5598/index.md)
Attackers can potentially leak private keys from FrodoKEM implementations in BC-JAVA via timing side-channel attacks due to non-constant time comparisons.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-5598?
CVE-2026-5598 is a high-severity vulnerability in Legion of the Bouncy Castle Inc. BC-JAVA, published on 15 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
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 affects BC-JAVA: from 1.71 before 1.80.2, from 1.81 before 1.81.1, from 1.82 before 1.84.
Weakness: CWE-385
Which versions are affected by CVE-2026-5598?
6 open source packages ship an affected version, including org.bouncycastle:bcprov-jdk14, org.bouncycastle:bcprov-jdk15to18 and org.bouncycastle:bcprov-jdk18on.
| Package | Affected | Fixed in |
|---|---|---|
org.bouncycastle:bcprov-jdk14 Maven | From 1.81 | 1.81.1 |
org.bouncycastle:bcprov-jdk14 Maven | From 1.81 | 1.81.1 |
org.bouncycastle:bcprov-jdk15to18 Maven | From 1.71 | 1.80.2 |
org.bouncycastle:bcprov-jdk15to18 Maven | From 1.71 | 1.80.2 |
org.bouncycastle:bcprov-jdk18on Maven | From 1.82 | 1.84 |
org.bouncycastle:bcprov-jdk18on Maven | From 1.82 | 1.84 |
Linux distribution packages (18)
eap7-bouncycastle Red Hat:jboss_enterprise_application_platform_els:7.4::el7 | All versions | 0:1.84.0-1.redhat_00001.1.el7eap |
eap7-bouncycastle-mail Red Hat:jboss_enterprise_application_platform_els:7.4::el7 | All versions | 0:1.84.0-1.redhat_00001.1.el7eap |
eap7-bouncycastle-pg Red Hat:jboss_enterprise_application_platform_els:7.4::el7 | All versions | 0:1.84.0-1.redhat_00001.1.el7eap |
eap7-bouncycastle-pkix Red Hat:jboss_enterprise_application_platform_els:7.4::el7 | All versions | 0:1.84.0-1.redhat_00001.1.el7eap |
eap7-bouncycastle-prov Red Hat:jboss_enterprise_application_platform_els:7.4::el7 | All versions | 0:1.84.0-1.redhat_00001.1.el7eap |
eap7-bouncycastle-util Red Hat:jboss_enterprise_application_platform_els:7.4::el7 | All versions | 0:1.84.0-1.redhat_00001.1.el7eap |
eap7-bouncycastle Red Hat:jboss_enterprise_application_platform_els:7.4::el8 | All versions | 0:1.84.0-1.redhat_00001.1.el8eap |
eap7-bouncycastle-mail Red Hat:jboss_enterprise_application_platform_els:7.4::el8 | All versions | 0:1.84.0-1.redhat_00001.1.el8eap |
eap7-bouncycastle-pg Red Hat:jboss_enterprise_application_platform_els:7.4::el8 | All versions | 0:1.84.0-1.redhat_00001.1.el8eap |
eap7-bouncycastle-pkix Red Hat:jboss_enterprise_application_platform_els:7.4::el8 | All versions | 0:1.84.0-1.redhat_00001.1.el8eap |
eap7-bouncycastle-prov Red Hat:jboss_enterprise_application_platform_els:7.4::el8 | All versions | 0:1.84.0-1.redhat_00001.1.el8eap |
eap7-bouncycastle-util Red Hat:jboss_enterprise_application_platform_els:7.4::el8 | All versions | 0:1.84.0-1.redhat_00001.1.el8eap |
eap7-bouncycastle Red Hat:jboss_enterprise_application_platform_els:7.4::el9 | All versions | 0:1.84.0-1.redhat_00001.1.el9eap |
eap7-bouncycastle-mail Red Hat:jboss_enterprise_application_platform_els:7.4::el9 | All versions | 0:1.84.0-1.redhat_00001.1.el9eap |
eap7-bouncycastle-pg Red Hat:jboss_enterprise_application_platform_els:7.4::el9 | All versions | 0:1.84.0-1.redhat_00001.1.el9eap |
eap7-bouncycastle-pkix Red Hat:jboss_enterprise_application_platform_els:7.4::el9 | All versions | 0:1.84.0-1.redhat_00001.1.el9eap |
eap7-bouncycastle-prov Red Hat:jboss_enterprise_application_platform_els:7.4::el9 | All versions | 0:1.84.0-1.redhat_00001.1.el9eap |
eap7-bouncycastle-util Red Hat:jboss_enterprise_application_platform_els:7.4::el9 | All versions | 0:1.84.0-1.redhat_00001.1.el9eap |
How do I fix CVE-2026-5598?
Upgrade org.bouncycastle:bcprov-jdk14 to 1.81.1 or later.
Is CVE-2026-5598 being exploited?
There is no known exploitation of CVE-2026-5598 in the wild and no public exploit code.
Sources
Also known as CLEANSTART-2026-TK91249, CLEANSTART-2026-WA32261, CLSA-2026-1785938101, DEBIAN-CVE-2026-5598, ECHO-bfec-8234-fda2, GHSA-p93r-85wp-75v3 and 53 more.