CVE-2026-12816

In Bouncy Castle for Java before 1.85, IESEngine stream-mode MAC forgery via length-dependent KDF split. This issue also affects Bouncy Castle for Java LTS before 2.73.12.

CVSS v3 7.5 HIGH

7.5^/10

CVSS v3 : HIGH

Vector :

Exploitability : 3.9 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact HIGH

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
https://github.com/bcgit/bc-java/commit/6d9e4bbaee9409713ada167e5f901554cbb084ac	Patch
https://github.com/bcgit/bc-java/wiki/CVE%E2%80%902026%E2%80%9012816	Third Party Advisory Patch

Configurations

Configuration 1 (hide)

OR	cpe:2.3:a:bouncycastle:bc-java::::::::
	cpe:2.3:a:bouncycastle:bouncy_castle_for_java_lts::::::::

History

No history.

Information

Published : 2026-08-03 04:16

Updated : 2026-09-02 14:38

NVD link : CVE-2026-12816

Mitre link : CVE-2026-12816

CVE.ORG link : CVE-2026-12816

JSON object : View

Products Affected

bouncycastle

bouncy_castle_for_java_lts
bc-java

CWE

CWE-354

Improper Validation of Integrity Check Value

{"id": "CVE-2026-12816", "cveTags": [], "metrics": {"ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-12816", "role": "CISA Coordinator", "options": [{"exploitation": "none"}, {"automatable": "yes"}, {"technicalImpact": "partial"}], "version": "2.0.3", "timestamp": "2026-08-03T15:20:07.709457Z"}}], "cvssMetricV31": [{"type": "Primary", "source": "nvd@nist.gov", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 7.5, "attackVector": "NETWORK", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N", "integrityImpact": "HIGH", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "NONE", "privilegesRequired": "NONE", "confidentialityImpact": "NONE"}, "impactScore": 3.6, "exploitabilityScore": 3.9}], "cvssMetricV40": [{"type": "Secondary", "source": "91579145-5d7b-4cc5-b925-a0262ff19630", "cvssData": {"Safety": "NOT_DEFINED", "version": "4.0", "Recovery": "NOT_DEFINED", "baseScore": 8.7, "Automatable": "NOT_DEFINED", "attackVector": "NETWORK", "baseSeverity": "HIGH", "valueDensity": "NOT_DEFINED", "vectorString": "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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:Amber", "exploitMaturity": "NOT_DEFINED", "providerUrgency": "AMBER", "userInteraction": "NONE", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "NONE", "subIntegrityImpact": "NONE", "vulnIntegrityImpact": "HIGH", "integrityRequirement": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "vulnAvailabilityImpact": "NONE", "availabilityRequirement": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "subConfidentialityImpact": "NONE", "vulnConfidentialityImpact": "NONE", "confidentialityRequirement": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "vulnerabilityResponseEffort": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED"}}]}, "affected": [{"source": "91579145-5d7b-4cc5-b925-a0262ff19630", "affectedData": [{"repo": "https://github.com/bcgit/bc-java", "vendor": "Legion of the Bouncy Castle Inc.", "modules": ["core"], "product": "BC-JAVA", "versions": [{"status": "affected", "version": "0", "lessThan": "1.85", "versionType": "maven"}], "platforms": ["all"], "packageURL": "pkg:maven/org.bouncycastle/bcprov-jdk18on", "packageName": "bcprov", "programFiles": ["IESEngine"], "collectionURL": "https://www.bouncycastle.org/download/bouncy-castle-java/", "defaultStatus": "unaffected"}, {"repo": "https://github.com/bcgit/bc-lts-java", "vendor": "Legion of the Bouncy Castle Inc.", "modules": ["core"], "product": "BC-LTS-JAVA", "versions": [{"status": "affected", "version": "2.73.0", "lessThan": "2.73.12", "versionType": "maven"}], "platforms": ["all"], "packageURL": "pkg:maven/org.bouncycastle/bcprov-lts8on", "packageName": "bcprov-lts8on", "programFiles": ["IESEngine"], "collectionURL": "https://www.bouncycastle.org/download/bouncy-castle-java-lts/", "defaultStatus": "unaffected"}]}], "published": "2026-08-03T04:16:39.330", "references": [{"url": "https://github.com/bcgit/bc-java/commit/6d9e4bbaee9409713ada167e5f901554cbb084ac", "tags": ["Patch"], "source": "91579145-5d7b-4cc5-b925-a0262ff19630"}, {"url": "https://github.com/bcgit/bc-java/wiki/CVE%E2%80%902026%E2%80%9012816", "tags": ["Third Party Advisory", "Patch"], "source": "91579145-5d7b-4cc5-b925-a0262ff19630"}], "vulnStatus": "Analyzed", "weaknesses": [{"type": "Secondary", "source": "91579145-5d7b-4cc5-b925-a0262ff19630", "description": [{"lang": "en", "value": "CWE-354"}]}], "descriptions": [{"lang": "en", "value": "In Bouncy Castle for Java before 1.85, IESEngine stream-mode MAC forgery via length-dependent KDF split. This issue also affects Bouncy Castle for Java LTS before 2.73.12."}], "lastModified": "2026-09-02T14:38:23.313", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:bouncycastle:bc-java:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "FA6A5663-2E62-44AA-8A64-A3CB0DC8813B", "versionEndExcluding": "1.85"}, {"criteria": "cpe:2.3:a:bouncycastle:bouncy_castle_for_java_lts:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "F5ED4F42-08FF-4642-815D-1ED0C82FDBD2", "versionEndIncluding": "2.73.11"}], "operator": "OR"}]}], "sourceIdentifier": "91579145-5d7b-4cc5-b925-a0262ff19630"}