GHSA-MX76-R943-RF8G

Vulnerability from github – Published: 2026-05-08 09:31 – Updated: 2026-07-07 21:30
VLAI
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
5.1 (Medium)
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
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{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 2.73.10"
      },
      "package": {
        "ecosystem": "Maven",
        "name": "org.bouncycastle:bcprov-lts8on"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2.73.0"
            },
            {
              "fixed": "2.73.11"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-8149"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-1068",
      "CWE-354"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-05-14T13:06:27Z",
    "nvd_published_at": "2026-05-08T07:16:29Z",
    "severity": "MODERATE"
  },
  "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.",
  "id": "GHSA-mx76-r943-rf8g",
  "modified": "2026-07-07T21:30:16Z",
  "published": "2026-05-08T09:31:30Z",
  "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"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "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",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Bouncy Castle LTS native GCM chunking can cause bad-tag exception on decryption"
}



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