CVE-2026-12803

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Source
https://cve.org/CVERecord?id=CVE-2026-12803
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-12803.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-12803
Downstream
CLEANSTART (9)
DEBIAN (1)
openSUSE (2)
SUSE (3)
UBUNTU (1)
Related
openSUSE (2)
SUSE (3)
Published
2026-08-03T02:52:20Z
Modified
2026-10-24T14:58:32Z
Severity
  • 8.7 (High) CVSS_V4 - CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/U:Amber CVSS Calculator
Summary
KCCMBlockCipher MAC does not bind nonce when AAD is absent (cross-nonce AEAD forgery)
Details

In Bouncy Castle for Java before 1.85, KCCMBlockCipher MAC does not bind nonce when AAD is absent (cross-nonce AEAD forgery). This issue also affects Bouncy Castle for Java LTS before 2.73.12.

Database specific 
{
    "cna_assigner":  "bcorg",
    "cwe_ids":  [
        "CWE-354"
    ],
    "osv_generated_from":  "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/12xxx/CVE-2026-12803.json"
}
References

Affected packages

Git / github.com/bcgit/bc-java

Affected ranges

Type
GIT
Repo
https://github.com/bcgit/bc-java
Events
Introduced
0 Unknown introduced commit / All previous commits are affected
Fixed
57fbd3c501f7a369f64eda311d6a709fc0bcae84
Fixed
697794413ebf7bc5e3fce609a707826ba52981af
Fixed
7d79aa76e984da85f2a541cae8ba2ae56e1713bc
Database specific
Show details 
{
    "extracted_events":  [
        {
            "cpe":  "cpe:2.3:a:bouncycastle:bc-java:*:*:*:*:*:*:*:*",
            "range":  [
                {
                    "introduced":  "0"
                },
                {
                    "fixed":  "1.85"
                }
            ],
            "source":  "CPE_RANGE"
        },
        {
            "range":  [
                {
                    "fixed":  "697794413ebf7bc5e3fce609a707826ba52981af"
                }
            ],
            "source":  "REFERENCES_COMMIT"
        },
        {
            "range":  [
                {
                    "fixed":  "7d79aa76e984da85f2a541cae8ba2ae56e1713bc"
                }
            ],
            "source":  "REFERENCES_COMMIT"
        }
    ]
}
Type
GIT
Repo
https://github.com/bcgit/bc-lts-java
Events
Introduced
468b5082f3f0971e80bf9edb7029c17b39b9ba0c
Fixed
f101b232c5d3e07ecdd504210a57e43831d6cd65
Database specific
Show details 
{
    "extracted_events":  [
        {
            "range":  [
                {
                    "introduced":  "2.73.0"
                },
                {
                    "fixed":  "2.73.12"
                }
            ],
            "source":  "AFFECTED_FIELD",
            "strategy":  "StandardRange"
        },
        {
            "cpe":  "cpe:2.3:a:bouncycastle:bouncy_castle_for_java_lts:*:*:*:*:*:*:*:*",
            "range":  [
                {
                    "introduced":  "0"
                },
                {
                    "last_affected":  "2.73.11"
                }
            ],
            "source":  "CPE_RANGE"
        }
    ]
}

Affected versions

Other
r1rv73
r1rv74
r1rv75
r1rv76
r1rv77
r1rv78
r1rv80
r1rv81
r1rv82
r1rv83
r1rv84
r2rv73dot0
r2rv73dot1
r2rv73dot10
r2rv73dot11
r2rv73dot3
r2rv73dot4
r2rv73dot6
r2rv73dot8
r2rv73dot9

Database specific

source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-12803.json"
vanir_signatures 
[
    {
        "deprecated":  false,
        "digest":  {
            "function_hash":  "7859619620194799728679201341619350374",
            "length":  1338
        },
        "id":  "CVE-2026-12803-23690617",
        "signature_type":  "Function",
        "signature_version":  "v1",
        "source":  "https://github.com/bcgit/bc-java/commit/697794413ebf7bc5e3fce609a707826ba52981af",
        "target":  {
            "file":  "core/src/main/java/org/bouncycastle/crypto/modes/KCCMBlockCipher.java",
            "function":  "processAAD"
        }
    },
    {
        "deprecated":  false,
        "digest":  {
            "function_hash":  "330085538170321426461012785600519507132",
            "length":  1402
        },
        "id":  "CVE-2026-12803-27bc2d79",
        "signature_type":  "Function",
        "signature_version":  "v1",
        "source":  "https://github.com/bcgit/bc-java/commit/7d79aa76e984da85f2a541cae8ba2ae56e1713bc",
        "target":  {
            "file":  "core/src/main/java/org/bouncycastle/crypto/modes/KCCMBlockCipher.java",
            "function":  "processAAD"
        }
    },
    {
        "deprecated":  false,
        "digest":  {
            "function_hash":  "340073630505974547917171180437211506149",
            "length":  2065
        },
        "id":  "CVE-2026-12803-2f11a1f4",
        "signature_type":  "Function",
        "signature_version":  "v1",
        "source":  "https://github.com/bcgit/bc-java/commit/697794413ebf7bc5e3fce609a707826ba52981af",
        "target":  {
            "file":  "core/src/main/java/org/bouncycastle/crypto/modes/KCCMBlockCipher.java",
            "function":  "processPacket"
        }
    },
    {
        "deprecated":  false,
        "digest":  {
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                "112282028145144829271635793220694313235",
                "55786641628166949157166300556499813953"
            ],
            "threshold":  0.9
        },
        "id":  "CVE-2026-12803-30871725",
        "signature_type":  "Line",
        "signature_version":  "v1",
        "source":  "https://github.com/bcgit/bc-java/commit/697794413ebf7bc5e3fce609a707826ba52981af",
        "target":  {
            "file":  "core/src/test/java/org/bouncycastle/crypto/test/DSTU7624Test.java"
        }
    },
    {
        "deprecated":  false,
        "digest":  {
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                "83462947891561411463727252308985034805",
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                "117066315017656844240980038846805238114",
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                "173318187833711217880871984916318727095",
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                "96488066762290290612443472085759584766",
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                "141237298968300724764502503401688499551",
                "258187989350374820795573964039784656828",
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                "252288185339127650541760491092180695283",
                "314769318678252706128544630536417110584",
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                "177721513311122820690794210071921301952",
                "110303873626780920422807307071198535551"
            ],
            "threshold":  0.9
        },
        "id":  "CVE-2026-12803-3859277f",
        "signature_type":  "Line",
        "signature_version":  "v1",
        "source":  "https://github.com/bcgit/bc-java/commit/7d79aa76e984da85f2a541cae8ba2ae56e1713bc",
        "target":  {
            "file":  "core/src/main/java/org/bouncycastle/crypto/modes/KCCMBlockCipher.java"
        }
    },
    {
        "deprecated":  false,
        "digest":  {
            "function_hash":  "297656122035220508493498791125555284103",
            "length":  2020
        },
        "id":  "CVE-2026-12803-53632105",
        "signature_type":  "Function",
        "signature_version":  "v1",
        "source":  "https://github.com/bcgit/bc-java/commit/7d79aa76e984da85f2a541cae8ba2ae56e1713bc",
        "target":  {
            "file":  "core/src/main/java/org/bouncycastle/crypto/modes/KCCMBlockCipher.java",
            "function":  "processPacket"
        }
    },
    {
        "deprecated":  false,
        "digest":  {
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            "threshold":  0.9
        },
        "id":  "CVE-2026-12803-8ad0bf64",
        "signature_type":  "Line",
        "signature_version":  "v1",
        "source":  "https://github.com/bcgit/bc-java/commit/697794413ebf7bc5e3fce609a707826ba52981af",
        "target":  {
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        "digest":  {
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            "length":  8161
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        "id":  "CVE-2026-12803-9cc10f1e",
        "signature_type":  "Function",
        "signature_version":  "v1",
        "source":  "https://github.com/bcgit/bc-java/commit/697794413ebf7bc5e3fce609a707826ba52981af",
        "target":  {
            "file":  "core/src/test/java/org/bouncycastle/crypto/test/DSTU7624Test.java",
            "function":  "CCMModeTests"
        }
    }
]
vanir_signatures_modified 
"2026-10-24T14:58:32Z"