Vulnerability-Lookup

GHSA-MX76-R943-RF8G

Vulnerability from github – Published: 2026-05-08 09:31 – Updated: 2026-07-07 21:30

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"
}

CVE-2026-8149 (GCVE-0-2026-8149)

Vulnerability from cvelistv5 – Published: 2026-05-08 06:01 – Updated: 2026-05-18 23:39

Title

GCM chunking can lead to bad tag exception on decryption

Summary

A vulnerability in Legion of the Bouncy Castle Inc. BC-LTS on Linux, X86_64, AVX, AVX-512f. This vulnerability is associated with program files gcm128w, gcm512w. This issue affects BC-LTS: from 2.73.0 before 2.73.11.

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/S:N/RE:M/U:Amber

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator (v2.0.3)

CWE

CWE-1068

Assigner

bcorg

References

1 reference

URL	Tags
https://github.com/bcgit/bc-java/wiki/CVE%E2%80%9…	vendor-advisory

Impacted products

1 product

Vendor	Product	Version
Legion of the Bouncy Castle Inc.	BC-LTS	Affected: 2.73.0 , < 2.73.11 (maven)

Credits

Michael Schäfer, Kiteworks

Show details on NVD website

JSON

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                  },
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                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-05-08T12:50:54.859989Z",
                "version": "2.0.3"
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Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

Action not permitted

GHSA-MX76-R943-RF8G

CVE-2026-8149 (GCVE-0-2026-8149)

Tags

Sightings

Nomenclature