« Back to list

CVE-2026-12852

Status: AnalyzedHigh (8.7)—

In Bouncy Castle for Java before 1.85, MLS wire decoder allocates attacker-declared opaque length before bounds check.

CVSS

Exploitation probability (EPSS)

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

🎯 ATT&CK techniques

How this vulnerability is exploited and what the attacker gains, in MITRE ATT&CK terms.

Vector AV:N/PR:N/UI:N indica explotación remota sin privilegios (T1190). CWE-789 (asignación de memoria sin validación) en decoder MLS causa denegación de servicio por agotamiento de memoria (T1499.004). BouncyCastle es aplicación expuesta de servidor.

Inferred by our analysis agent from the official description, CVSS vector and CWE, and checked by a supervisor. May contain errors.

🛡️ ATT&CK mitigations that cover these techniques

Filter Network TrafficVulnerability ScanningPrivileged Account ManagementNetwork SegmentationLimit Access to Resource Over NetworkApplication Isolation and Sandboxing

Affected technologies (1)

Bouncycastle — Bc-java

CWEs

References

Raw JSON (NVD)

Show
{
  "id": "CVE-2026-12852",
  "cveTags": [],
  "metrics": {
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-12852",
          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "version": "2.0.3",
          "timestamp": "2026-08-03T15:11:15.405624Z"
        }
      }
    ],
    "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:N/A:H",
          "integrityImpact": "NONE",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "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:N/VA:H/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": "NONE",
          "integrityRequirement": "NOT_DEFINED",
          "modifiedAttackVector": "NOT_DEFINED",
          "subAvailabilityImpact": "NONE",
          "vulnAvailabilityImpact": "HIGH",
          "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": [
            "mls"
          ],
          "product": "BC-JAVA",
          "versions": [
            {
              "status": "affected",
              "version": "1.73",
              "lessThan": "1.85",
              "versionType": "maven"
            }
          ],
          "platforms": [
            "all"
          ],
          "packageURL": "pkg:maven/org.bouncycastle/bcmls-jdk18on",
          "packageName": "bcmls",
          "programFiles": [
            "MLSInputStream"
          ],
          "collectionURL": "https://www.bouncycastle.org/download/bouncy-castle-java/",
          "defaultStatus": "unaffected"
        }
      ]
    }
  ],
  "published": "2026-08-03T04:16:39.640",
  "references": [
    {
      "url": "https://github.com/bcgit/bc-java/commit/a747038bb5bbd5e29fb2b7607ab38af1fd8d1790",
      "tags": [
        "Patch"
      ],
      "source": "91579145-5d7b-4cc5-b925-a0262ff19630"
    },
    {
      "url": "https://github.com/bcgit/bc-java/wiki/CVE%E2%80%902026%E2%80%9012852",
      "tags": [
        "Third Party Advisory"
      ],
      "source": "91579145-5d7b-4cc5-b925-a0262ff19630"
    }
  ],
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "type": "Secondary",
      "source": "91579145-5d7b-4cc5-b925-a0262ff19630",
      "description": [
        {
          "lang": "en",
          "value": "CWE-789"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "In Bouncy Castle for Java before 1.85, MLS wire decoder allocates attacker-declared opaque length before bounds check."
    }
  ],
  "lastModified": "2026-08-28T16:16:19.197",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:bouncycastle:bc-java:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "FA6A5663-2E62-44AA-8A64-A3CB0DC8813B",
              "versionEndExcluding": "1.85"
            }
          ],
          "operator": "OR"
        }
      ]
    }
  ],
  "sourceIdentifier": "91579145-5d7b-4cc5-b925-a0262ff19630"
}