CVE-2026-8149: Bouncy Castle Bouncy Castle LTS Native GCM Vulnerability

MODERATE
Advisory Identifier: GHSA-mx76-r943-rf8g
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CWE-1068 CWE-354
Published
Advisory Summary

CVE-2026-8149 is a MODERATE bouncy castle lts native gcm vulnerability (CWE-1068: Inconsistency Between Implementation and Documented Design) affecting Bouncy Castle libraries in the Maven ecosystem. The issue involves bouncy castle lts native gcm chunking can cause bad-tag exception on decryption. Remediation is available by upgrading affected packages to version 2.73.11.

CVE-2026-8149 at a Glance

CVE Identifier CVE-2026-8149
GHSA Identifier GHSA-mx76-r943-rf8g
Severity MODERATE
CVSS v3.1 Base Score N/A
CWE Classification CWE-1068: Inconsistency Between Implementation and Documented Design
Affected Product Bouncy Castle
Package Ecosystem Maven
Published Date
Last Updated

How to Fix CVE-2026-8149

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-lts8on fixed: 2.73.11 
<dependency>
    <groupId>org.bouncycastle</groupId>
    <artifactId>bcprov-lts8on</artifactId>
    <version>2.73.11</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-2026-8149, 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 2.73.11), 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-1068: Inconsistency Between Implementation and Documented Design, where the implementation of the product is not consistent with the design as described within the relevant documentation. 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

In Bouncy Castle LTS for Java, the AES/GCM native implementation used on Intel CPUs with AES PAA instruction sets (AVX / VAES / VAESF variants) can intermittently produce an incorrect authentication tag verification result during decryption when the ciphertext is fed in via a mix of `update()` calls followed by `doFinal()`. It is possible to work around it by either using `doFinal()` only (as the BCJSSE does) or by configuring the module to run in pure Java mode, by setting the system property "org.bouncycastle.native.cpu_variant" to java.

CVE-2026-8149 Affected Bouncy Castle Versions

1 component(s)
Fixed Versions:
2.73.11
Product / Package Ecosystem Affected Versions Fixed Version
org.bouncycastle:bcprov-lts8on
maven/org.bouncycastle/bcprov-lts8on
Maven
≥ 2.73.0
< 2.73.11
2.73.11

References

NVD — CVE-2026-8149 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-8149
GitHub Advisory / Wiki ADVISORY
https://github.com/bcgit/bc-java/wiki/CVE%E2%80%902026%E2%80%908149

Frequently Asked Questions

What is CVE-2026-8149?
CVE-2026-8149 is a security vulnerability in Bouncy Castle involving Bouncy Castle LTS native GCM chunking can cause bad-tag exception on decryption under CWE-1068: Inconsistency Between Implementation and Documented Design.
Which Bouncy Castle versions are affected?
Affected versions include releases prior to 2.73.11 across affected packages: org.bouncycastle:bcprov-lts8on.
What version fixes CVE-2026-8149?
Upgrading to 2.73.11 (or the latest patched release for your respective branch) resolves the vulnerability.
Is bcprov-lts8on affected?
Yes, org.bouncycastle:bcprov-lts8on is affected in releases prior to 2.73.11. Upgrade your dependency to 2.73.11 or later.
What CWE is associated with CVE-2026-8149?
CVE-2026-8149 is classified under CWE-1068: Inconsistency Between Implementation and Documented Design (The implementation of the product is not consistent with the design as described within the relevant documentation.).
How can I check Maven dependencies for CVE-2026-8149?
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
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-mx76-r943-rf8g",
  "modified" : "2026-07-07T21:30:16Z",
  "published" : "2026-05-08T09:31:30Z",
  "aliases" : [ "CVE-2026-8149" ],
  "summary" : "Bouncy Castle LTS native GCM chunking can cause bad-tag exception on decryption",
  "details" : "In Bouncy Castle LTS for Java, the AES/GCM native implementation used on Intel CPUs with AES PAA instruction sets (AVX / VAES / VAESF variants) can intermittently produce an incorrect authentication tag verification result during decryption when the ciphertext is fed in via a mix of `update()` calls followed by `doFinal()`. It is possible to work around it by either using `doFinal()` only (as the BCJSSE does) or by configuring the module to run in pure Java mode, by setting the system property \"org.bouncycastle.native.cpu_variant\" to java.",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "org.bouncycastle:bcprov-lts8on"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "2.73.0"
      }, {
        "fixed" : "2.73.11"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 2.73.10"
    }
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-8149"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/bcgit/bc-java/wiki/CVE%E2%80%902026%E2%80%908149"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-1068", "CWE-354" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-05-14T13:06:27Z",
    "nvd_published_at" : "2026-05-08T07:16:29Z"
  }
}