GCVE Workshop - 22 September 2026 (14:00-18:00), Luxembourg Before The Vulnopticon Conference - Registration

CVE-2026-87732 (GCVE-0-2026-87732)

Vulnerability from cvelistv5 – Published: 2026-09-09 04:03 – Updated: 2026-09-09 13:11
VLAI
Summary
An issue was discovered in the mirage-crypto package before 2.2.0 for OCaml. The AES.GCM.authenticate_decrypt_into and Chacha20.authenticate_decrypt_into functions write the decrypted plaintext into a caller-provided buffer and only then compares the tag. On a forged tag, the functions returns false, but the destination buffer already holds the full plaintext.
Severity
6.2 (Medium)
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
SSVC
Exploitation: poc Automatable: no Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-09-09 13:11 UTC
CWE
  • CWE-347 - Improper Verification of Cryptographic Signature
Assigner
References
Impacted products
Vendor Product Version CPE status
OCaml mirage-crypto Affected: 0 , < 2.2.0 (semver)
guessed Create a notification for this product.
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-87732",
                "options": [
                  {
                    "Exploitation": "poc"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-09-09T13:11:34.596764Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-09-09T13:11:54.773Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "references": [
          {
            "tags": [
              "exploit"
            ],
            "url": "https://osv.dev/vulnerability/OSEC-2026-12"
          }
        ],
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "packageURL": "pkg:opam/mirage-crypto",
          "product": "mirage-crypto",
          "vendor": "OCaml",
          "versions": [
            {
              "lessThan": "2.2.0",
              "status": "affected",
              "version": "0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "An issue was discovered in the mirage-crypto package before 2.2.0 for OCaml. The AES.GCM.authenticate_decrypt_into and Chacha20.authenticate_decrypt_into functions write the decrypted plaintext into a caller-provided buffer and only then compares the tag. On a forged tag, the functions returns false, but the destination buffer already holds the full plaintext."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "LOCAL",
            "availabilityImpact": "NONE",
            "baseScore": 6.2,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "NONE",
            "integrityImpact": "HIGH",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N",
            "version": "3.1"
          },
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
          ]
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-347",
              "description": "CWE-347 Improper Verification of Cryptographic Signature",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-09T04:05:10.227Z",
        "orgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca",
        "shortName": "mitre"
      },
      "references": [
        {
          "url": "https://osv.dev/vulnerability/OSEC-2026-12"
        }
      ],
      "x_generator": {
        "engine": "CVE-Request-form 0.0.1"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca",
    "assignerShortName": "mitre",
    "cveId": "CVE-2026-87732",
    "datePublished": "2026-09-09T04:03:53.056Z",
    "dateReserved": "2026-09-09T04:03:52.629Z",
    "dateUpdated": "2026-09-09T13:11:54.773Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-87732",
      "date": "2026-09-16",
      "epss": "0.00077",
      "percentile": "0.00128"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-87732\",\"sourceIdentifier\":\"cve@mitre.org\",\"published\":\"2026-09-09T05:18:20.277\",\"lastModified\":\"2026-09-09T16:04:24.933\",\"vulnStatus\":\"Deferred\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"An issue was discovered in the mirage-crypto package before 2.2.0 for OCaml. The AES.GCM.authenticate_decrypt_into and Chacha20.authenticate_decrypt_into functions write the decrypted plaintext into a caller-provided buffer and only then compares the tag. On a forged tag, the functions returns false, but the destination buffer already holds the full plaintext.\"}],\"affected\":[{\"source\":\"cve@mitre.org\",\"affectedData\":[{\"vendor\":\"OCaml\",\"product\":\"mirage-crypto\",\"defaultStatus\":\"unaffected\",\"packageURL\":\"pkg:opam/mirage-crypto\",\"versions\":[{\"version\":\"0\",\"lessThan\":\"2.2.0\",\"versionType\":\"semver\",\"status\":\"affected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"cve@mitre.org\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N\",\"baseScore\":6.2,\"baseSeverity\":\"MEDIUM\",\"attackVector\":\"LOCAL\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"NONE\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"NONE\"},\"exploitabilityScore\":2.5,\"impactScore\":3.6}],\"ssvcV203\":[{\"source\":\"134c704f-9b21-4f2e-91b3-4a467353bcc0\",\"ssvcData\":{\"timestamp\":\"2026-09-09T13:11:34.596764Z\",\"id\":\"CVE-2026-87732\",\"options\":[{\"exploitation\":\"poc\"},{\"automatable\":\"no\"},{\"technicalImpact\":\"partial\"}],\"role\":\"CISA Coordinator\",\"version\":\"2.0.3\"}}]},\"weaknesses\":[{\"source\":\"cve@mitre.org\",\"type\":\"Secondary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-347\"}]}],\"references\":[{\"url\":\"https://osv.dev/vulnerability/OSEC-2026-12\",\"source\":\"cve@mitre.org\"},{\"url\":\"https://osv.dev/vulnerability/OSEC-2026-12\",\"source\":\"134c704f-9b21-4f2e-91b3-4a467353bcc0\"}]}}",
    "vulnrichment": {
      "containers": "{\"adp\": [{\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2026-87732\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"poc\"}, {\"Automatable\": \"no\"}, {\"Technical Impact\": \"partial\"}], \"version\": \"2.0.3\", \"timestamp\": \"2026-09-09T13:11:34.596764Z\"}}}], \"references\": [{\"url\": \"https://osv.dev/vulnerability/OSEC-2026-12\", \"tags\": [\"exploit\"]}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2026-09-09T13:11:51.667Z\"}}], \"cna\": {\"metrics\": [{\"format\": \"CVSS\", \"cvssV3_1\": {\"scope\": \"UNCHANGED\", \"version\": \"3.1\", \"baseScore\": 6.2, \"attackVector\": \"LOCAL\", \"baseSeverity\": \"MEDIUM\", \"vectorString\": \"CVSS:3.1/AV:L/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\"}, \"scenarios\": [{\"lang\": \"en\", \"value\": \"GENERAL\"}]}], \"affected\": [{\"vendor\": \"OCaml\", \"product\": \"mirage-crypto\", \"versions\": [{\"status\": \"affected\", \"version\": \"0\", \"lessThan\": \"2.2.0\", \"versionType\": \"semver\"}], \"packageURL\": \"pkg:opam/mirage-crypto\", \"defaultStatus\": \"unaffected\"}], \"references\": [{\"url\": \"https://osv.dev/vulnerability/OSEC-2026-12\"}], \"x_generator\": {\"engine\": \"CVE-Request-form 0.0.1\"}, \"descriptions\": [{\"lang\": \"en\", \"value\": \"An issue was discovered in the mirage-crypto package before 2.2.0 for OCaml. The AES.GCM.authenticate_decrypt_into and Chacha20.authenticate_decrypt_into functions write the decrypted plaintext into a caller-provided buffer and only then compares the tag. On a forged tag, the functions returns false, but the destination buffer already holds the full plaintext.\"}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-347\", \"description\": \"CWE-347 Improper Verification of Cryptographic Signature\"}]}], \"providerMetadata\": {\"orgId\": \"8254265b-2729-46b6-b9e3-3dfca2d5bfca\", \"shortName\": \"mitre\", \"dateUpdated\": \"2026-09-09T04:05:10.227Z\"}}}",
      "cveMetadata": "{\"cveId\": \"CVE-2026-87732\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-09-09T13:11:54.773Z\", \"dateReserved\": \"2026-09-09T04:03:52.629Z\", \"assignerOrgId\": \"8254265b-2729-46b6-b9e3-3dfca2d5bfca\", \"datePublished\": \"2026-09-09T04:03:53.056Z\", \"assignerShortName\": \"mitre\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





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.


Detection rules are retrieved from Rulezet.


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.