dbcve.org
Improper Input ValidationWeakness · CWE-20

CVE-2026-59650

CRITICAL · 9.3 CVSS v4.0 Published 2026-08-03
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click 2 weeks old

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
In Bouncy Castle for Java before 1.85, MTI/A0 DH agreement exponentiates unvalidated peer value. This issue also affects Bouncy Castle for Java LTS before 2.73.12.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Bouncy Castle for Java's MTI/A0 DH key agreement implementation exponentiates an unvalidated peer value without proper bounds checking. This missing validation in the Diffie-Hellman key exchange allows potentially malicious peer public key values to be processed directly in cryptographic operations, risking cryptographic weakness or resource exhaustion attacks.

MitigationUpgrade Bouncy Castle Java to version 1.85 or later, or LTS version 2.73.12 or later, which implement proper validation of peer values before DH exponentiation.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
Authentication
X
User interaction
None
Scope
X

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:Amber

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify Bouncy Castle Java in your environment
    Search for bcprov-*.jar or bouncycastle JAR files in your application lib directories, Maven/Gradle dependencies, or classpath. Also check for the org.bouncycastle package in your runtime.
    Affected if Bouncy Castle Java library is present in your environment
  2. Determine the installed Bouncy Castle version
    Inspect the MANIFEST.MF file inside the bcprov JAR for Bundle-Version, or check your build file (pom.xml/gradle) for the bcprov dependency version, or run: java -cp bcprov-*.jar org.bouncycastle.util.Version
    Affected if Version is before 1.85 (for standard releases) or before 2.73.12 (for LTS releases)
  3. Check for MTI/A0 DH key agreement usage
    Search your codebase for usage of org.bouncycastle.crypto.agreement.DHAgreement or algorithm specifiers indicating DH key exchange. Look for imports of DHBasicAgreement or usage of KeyAgreement.getInstance("DH").
    Affected if Your code performs Diffie-Hellman key agreement operations using Bouncy Castle
  4. Verify DH parameter validation is implemented
    Review your key agreement code to confirm if DH parameters (prime, generator) are validated before use. Check for explicit parameter validation checks or reliance on Bouncy Castle's built-in validation.
    Affected if DH parameters from peers are used without validation in key agreement operations

You are affected if Bouncy Castle Java versions before 1.85 (or LTS before 2.73.12) are installed AND your application performs DH key agreement without validating incoming peer values.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade Bouncy Castle Java to version 1.85 or later, or LTS version 2.73.12 or later, which implement proper validation of peer values before DH exponentiation.

Recommended fix Moderate confidence

Bouncy Castle Java 2.73.12 (LTS) or 1.85+ (mainline)

  1. 1. Identify the current Bouncy Castle for Java version in your project (check pom.xml, build.gradle, or dependency management)
  2. 2. Determine if you are using the main release line or LTS release line
  3. 3. If using main release: upgrade org.bouncycastle:bcprov-jdk15to18 (or bcprov-jdk15on) to version 1.85 or later
  4. 4. If using LTS release: upgrade org.bouncycastle:bcprov-jdk15to18 to version 2.73.12 or later
  5. 5. Rebuild and test your application to verify the upgrade does not introduce regressions
  6. 6. Verify the upgrade was successful by checking the runtime Bouncy Castle version
Caveat Review Bouncy Castle release notes for version 1.85 and 2.73.12 for any API changes or deprecations that may affect your usage

Generated from the published advisory — verify against the referenced sources before acting.

Have this fixed Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing12.0 h
  • Review / QA4.0 h
28.0 hours of engineering $4,760
Get help mitigating

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $7,616.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2026-59650 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-59650 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data