FKIE_CVE-2026-17508
Vulnerability from fkie_nvd - Published: 2026-10-02 08:17 - Updated: 2026-10-02 18:17
Severity
Summary
In Bouncy Castle for Java before 1.86, several password-based key derivation entry points ran the KDF with cost parameters taken from the untrusted input being processed, without bounding them, so a small input could dictate an arbitrary amount of work before any password or integrity check could reject it. The affected paths are the RFC 9579 PBMAC1 MAC calculator builders, which took the PBKDF2 iteration count and derived-key length straight out of PBMAC1Params (JcePBMac1CalculatorBuilder, and PKCS12PBEUtils.createPBMac1Calculator reached from PKCS12PfxPdu.isMacValid); the scrypt parallelization parameter p in the PKCS#8 and PKCS#12 cost guards, which bounded only the cost parameter N and the block size r even though the scratch buffer scales with r times p, so the configured memory ceiling could be evaded entirely; the raw JCA PBKDF2 provider (org.bouncycastle.jcajce.provider.symmetric.PBEPBKDF2); and the bcrypt round count read from an encrypted OpenSSH v1 private key's own kdfoptions. Each now bounds the parameter before deriving, in line with the caps already applied elsewhere in the tree, with the OpenSSH round count configurable through the new org.bouncycastle.openssh.max_rounds property. This completes the bounding begun in 1.85 for the PKCS#8 / PBES2 decryptors (CVE-2026-15055). This issue also affects Bouncy Castle for Java LTS before 2.73.13, and Bouncy Castle for Java FIPS (BC-FJA) before bcpkix-fips 1.0.13 (1.0.X series), 2.0.13 (2.0.X series) and 2.1.13 (2.1.X series).
References
Impacted products
| Vendor | Product | Version |
|---|
{
"affected": [
{
"affectedData": [
{
"collectionURL": "https://www.bouncycastle.org/download/bouncy-castle-java/",
"defaultStatus": "unaffected",
"modules": [
"pkix"
],
"packageName": "bcpkix",
"packageURL": "pkg:maven/org.bouncycastle/bcpkix-jdk18on",
"platforms": [
"all"
],
"product": "BC-JAVA",
"programFiles": [
"JcePBMac1CalculatorBuilder",
"PKCS12PBEUtils",
"JcePKCSPBEInputDecryptorProviderBuilder",
"JceOpenSSLPKCS8DecryptorProviderBuilder"
],
"repo": "https://github.com/bcgit/bc-java",
"vendor": "Legion of the Bouncy Castle Inc.",
"versions": [
{
"lessThan": "1.86",
"status": "affected",
"version": "0",
"versionType": "maven"
}
]
},
{
"collectionURL": "https://www.bouncycastle.org/download/bouncy-castle-java/",
"defaultStatus": "unaffected",
"modules": [
"core",
"prov"
],
"packageName": "bcprov",
"packageURL": "pkg:maven/org.bouncycastle/bcprov-jdk18on",
"platforms": [
"all"
],
"product": "BC-JAVA",
"programFiles": [
"PBEPBKDF2",
"OpenSSHPrivateKeyUtil"
],
"repo": "https://github.com/bcgit/bc-java",
"vendor": "Legion of the Bouncy Castle Inc.",
"versions": [
{
"lessThan": "1.86",
"status": "affected",
"version": "0",
"versionType": "maven"
}
]
},
{
"collectionURL": "https://www.bouncycastle.org/download/bouncy-castle-java-lts/",
"defaultStatus": "unaffected",
"modules": [
"pkix"
],
"packageName": "bcpkix-lts8on",
"packageURL": "pkg:maven/org.bouncycastle/bcpkix-lts8on",
"platforms": [
"all"
],
"product": "BC-LTS-JAVA",
"programFiles": [
"JcePBMac1CalculatorBuilder",
"PKCS12PBEUtils",
"JcePKCSPBEInputDecryptorProviderBuilder",
"JceOpenSSLPKCS8DecryptorProviderBuilder"
],
"repo": "https://github.com/bcgit/bc-lts-java",
"vendor": "Legion of the Bouncy Castle Inc.",
"versions": [
{
"lessThan": "2.73.13",
"status": "affected",
"version": "2.73.0",
"versionType": "maven"
}
]
},
{
"collectionURL": "https://www.bouncycastle.org/download/bouncy-castle-java-lts/",
"defaultStatus": "unaffected",
"modules": [
"core",
"prov"
],
"packageName": "bcprov-lts8on",
"packageURL": "pkg:maven/org.bouncycastle/bcprov-lts8on",
"platforms": [
"all"
],
"product": "BC-LTS-JAVA",
"programFiles": [
"PBEPBKDF2",
"OpenSSHPrivateKeyUtil"
],
"repo": "https://github.com/bcgit/bc-lts-java",
"vendor": "Legion of the Bouncy Castle Inc.",
"versions": [
{
"lessThan": "2.73.13",
"status": "affected",
"version": "2.73.0",
"versionType": "maven"
}
]
},
{
"collectionURL": "https://www.bouncycastle.org/download/bouncy-castle-java-fips/",
"defaultStatus": "unaffected",
"packageName": "bcpkix-fips",
"packageURL": "pkg:maven/org.bouncycastle/bcpkix-fips",
"platforms": [
"all"
],
"product": "BC-FJA",
"vendor": "Legion of the Bouncy Castle Inc.",
"versions": [
{
"lessThan": "1.0.13",
"status": "affected",
"version": "1.0.0",
"versionType": "maven"
},
{
"lessThan": "2.0.13",
"status": "affected",
"version": "2.0.0",
"versionType": "maven"
},
{
"lessThan": "2.1.13",
"status": "affected",
"version": "2.1.0",
"versionType": "maven"
}
]
}
],
"source": "91579145-5d7b-4cc5-b925-a0262ff19630"
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In Bouncy Castle for Java before 1.86, several password-based key derivation entry points ran the KDF with cost parameters taken from the untrusted input being processed, without bounding them, so a small input could dictate an arbitrary amount of work before any password or integrity check could reject it. The affected paths are the RFC 9579 PBMAC1 MAC calculator builders, which took the PBKDF2 iteration count and derived-key length straight out of PBMAC1Params (JcePBMac1CalculatorBuilder, and PKCS12PBEUtils.createPBMac1Calculator reached from PKCS12PfxPdu.isMacValid); the scrypt parallelization parameter p in the PKCS#8 and PKCS#12 cost guards, which bounded only the cost parameter N and the block size r even though the scratch buffer scales with r times p, so the configured memory ceiling could be evaded entirely; the raw JCA PBKDF2 provider (org.bouncycastle.jcajce.provider.symmetric.PBEPBKDF2); and the bcrypt round count read from an encrypted OpenSSH v1 private key\u0027s own kdfoptions. Each now bounds the parameter before deriving, in line with the caps already applied elsewhere in the tree, with the OpenSSH round count configurable through the new org.bouncycastle.openssh.max_rounds property. This completes the bounding begun in 1.85 for the PKCS#8 / PBES2 decryptors (CVE-2026-15055). This issue also affects Bouncy Castle for Java LTS before 2.73.13, and Bouncy Castle for Java FIPS (BC-FJA) before bcpkix-fips 1.0.13 (1.0.X series), 2.0.13 (2.0.X series) and 2.1.13 (2.1.X series)."
}
],
"id": "CVE-2026-17508",
"lastModified": "2026-10-02T18:17:03.370",
"metrics": {
"cvssMetricV40": [
{
"cvssData": {
"Automatable": "NOT_DEFINED",
"Recovery": "NOT_DEFINED",
"Safety": "NOT_DEFINED",
"attackComplexity": "LOW",
"attackRequirements": "NONE",
"attackVector": "NETWORK",
"availabilityRequirement": "NOT_DEFINED",
"baseScore": 5.3,
"baseSeverity": "MEDIUM",
"confidentialityRequirement": "NOT_DEFINED",
"exploitMaturity": "NOT_DEFINED",
"integrityRequirement": "NOT_DEFINED",
"modifiedAttackComplexity": "NOT_DEFINED",
"modifiedAttackRequirements": "NOT_DEFINED",
"modifiedAttackVector": "NOT_DEFINED",
"modifiedPrivilegesRequired": "NOT_DEFINED",
"modifiedSubAvailabilityImpact": "NOT_DEFINED",
"modifiedSubConfidentialityImpact": "NOT_DEFINED",
"modifiedSubIntegrityImpact": "NOT_DEFINED",
"modifiedUserInteraction": "NOT_DEFINED",
"modifiedVulnAvailabilityImpact": "NOT_DEFINED",
"modifiedVulnConfidentialityImpact": "NOT_DEFINED",
"modifiedVulnIntegrityImpact": "NOT_DEFINED",
"privilegesRequired": "NONE",
"providerUrgency": "AMBER",
"subAvailabilityImpact": "NONE",
"subConfidentialityImpact": "NONE",
"subIntegrityImpact": "NONE",
"userInteraction": "PASSIVE",
"valueDensity": "NOT_DEFINED",
"vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:L/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",
"version": "4.0",
"vulnAvailabilityImpact": "LOW",
"vulnConfidentialityImpact": "NONE",
"vulnIntegrityImpact": "NONE",
"vulnerabilityResponseEffort": "NOT_DEFINED"
},
"source": "91579145-5d7b-4cc5-b925-a0262ff19630",
"type": "Secondary"
}
],
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"id": "CVE-2026-17508",
"options": [
{
"exploitation": "none"
},
{
"automatable": "no"
},
{
"technicalImpact": "partial"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-10-02T17:43:15.561288Z",
"version": "2.0.3"
}
}
]
},
"published": "2026-10-02T08:17:01.490",
"references": [
{
"source": "91579145-5d7b-4cc5-b925-a0262ff19630",
"url": "https://github.com/bcgit/bc-java/commit/20ed9e203caec91d25cd386ceb6d364e9b068f67"
},
{
"source": "91579145-5d7b-4cc5-b925-a0262ff19630",
"url": "https://github.com/bcgit/bc-java/commit/442393bf187c914b1e66fbed4fab532a1fe06c6a"
},
{
"source": "91579145-5d7b-4cc5-b925-a0262ff19630",
"url": "https://github.com/bcgit/bc-java/commit/480d878aa6f7dc8b20403064f304bbe0decbbb1a"
},
{
"source": "91579145-5d7b-4cc5-b925-a0262ff19630",
"url": "https://github.com/bcgit/bc-java/commit/766a31026ac24ed3c6cad8662058ba450c338da1"
},
{
"source": "91579145-5d7b-4cc5-b925-a0262ff19630",
"url": "https://github.com/bcgit/bc-java/commit/882fdab53f6c4c150a5d6a4e6ef1fc05d382385a"
},
{
"source": "91579145-5d7b-4cc5-b925-a0262ff19630",
"url": "https://github.com/bcgit/bc-java/commit/e72bc0681ff4227fced912ef7394daf7b7d57bb3"
},
{
"source": "91579145-5d7b-4cc5-b925-a0262ff19630",
"url": "https://github.com/bcgit/bc-java/wiki/CVE%E2%80%902026%E2%80%9017508"
}
],
"sourceIdentifier": "91579145-5d7b-4cc5-b925-a0262ff19630",
"vulnStatus": "Undergoing Analysis",
"weaknesses": [
{
"description": [
{
"lang": "en",
"value": "CWE-770"
}
],
"source": "91579145-5d7b-4cc5-b925-a0262ff19630",
"type": "Secondary"
}
]
}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
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.
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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
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Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.
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