CVE-2026-8149: Bouncy Castle BC-LTS GCM decryption failure on X86_64 Linux

CVE-2026-8149 · Severity: medium · CVSS 4 · Published 2026-05-08

Bouncy Castle, a widely used Java library for encryption and secure communications, contains a flaw in its FIPS-compliant Java API. On specific Linux systems using modern Intel processors, certain encryption operations may fail or behave inconsistently. This can lead to service disruptions or application errors when processing encrypted data, potentially impacting the reliability of secure business transactions.

Technologies: org.bouncycastle:bc-fips (Maven), org.bouncycastle:bcprov-lts8on (Maven). Vendors: Legion of the Bouncy Castle, Legion of the Bouncy Castle Inc., Maven.

Quick answers

Is CVE-2026-8149 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-8149 being exploited in the wild.
How severe is CVE-2026-8149?
Medium severity, with a CVSS score of 4, published 8 May 2026.
Which products and versions are affected?
Legion of the Bouncy Castle BC-FIPS 2.1.0 - 2.1.2; Legion of the Bouncy Castle BC-FIPS Java API 2.1.0 through 2.1.2; Legion of the Bouncy Castle Inc. BC-FJA 2.1.0 to 2.1.2; Legion of the Bouncy Castle Inc. BC-LTS 2.73.0 to 2.73.10; and 2 more.
Is there a fix for CVE-2026-8149?
Yes. org.bouncycastle:bcprov-lts8on (Maven): upgrade to 2.73.11 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-8149 attacked?
It is attacked with local access, in a software library.
Am I affected by CVE-2026-8149?
Check whether you run Legion of the Bouncy Castle BC-FIPS, Legion of the Bouncy Castle BC-FIPS Java API, Legion of the Bouncy Castle Inc. BC-FJA or one of the others listed at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • org.bouncycastle:bcprov-lts8on (Maven): upgrade to 2.73.11 or later
    # set org.bouncycastle:bcprov-lts8on to 2.73.11 in your pom.xml or build.gradle

Technical details

A vulnerability exists in the Legion of the Bouncy Castle BC-FJA BC-FIPS library (versions 2.1.0 through 2.1.2) specifically within the gcm128w and gcm512w program files. The issue is classified as CWE-1068 (Inconsistency Between Implementation and Documented Design) and affects Linux environments on X86_64 architecture utilizing AVX and AVX-512f instruction sets. The flaw involves GCM chunking which can lead to 'bad tag' exceptions during decryption. An attacker with local access could potentially trigger these inconsistencies to cause a denial-of-service (availability impact) by forcing decryption failures. No patch is explicitly detailed in the primary advisory, though related LTS versions (BC-LTS) fixed similar behavior in version 2.73.11.

Affected products

  • Legion of the Bouncy Castle BC-FJA BC-FIPS (bc-fips) 2.1.0 - 2.1.2

Identifiers

  • CVE-2026-8149
  • GHSA-mx76-r943-rf8g

Timeline

  • 2026-05-08: disclosed
  • 2026-05-08: advisory: Published to GitHub Advisory Database and NVD

References

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