CVE-2026-119194 (GCVE-0-2026-119194)

Vulnerability from cvelistv5 – Published: 2026-10-29 19:38 – Updated: 2026-10-29 19:38
VLAI
Title
pyasn1: Quadratic CPU use in schemaless BER/CER/DER container decoding
Summary
pyasn1 is a generic ASN.1 library for Python. From 0.3.3 until 0.6.5, schemaless container decoding stores every decoded component's TagSet in a growing set even though only one-versus-multiple tag types must be distinguished. Attacker-controlled BER, CER, or DER input contains many distinct long tag IDs whose TagSet hashes collide. Each later set insertion compares against an increasing number of earlier colliding tags in ConstructedPayloadDecoderBase._decodeComponentsSchemaless, producing quadratic CPU work while decoded values and order remain valid. Repeated inputs can exhaust decoder CPU and reduce service availability. This issue is fixed in version 0.6.5.
Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CWE
  • CWE-407 - Inefficient Algorithmic Complexity
Assigner
GitHub_M CNA under the mitre root
CNA scorecard C 72/100 over 7978 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
pyasn1 pyasn1 Affected: >= 0.3.3, < 0.6.5
guessed Create a notification for this product.
Show details on NVD website
To clipboard 

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        }
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            "baseScore": 7.5,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "NONE",
            "integrityImpact": "NONE",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
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            "version": "3.1"
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      ],
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              "description": "CWE-407: Inefficient Algorithmic Complexity",
              "lang": "en",
              "type": "CWE"
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      "providerMetadata": {
        "dateUpdated": "2026-10-29T19:38:14.056Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
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          "name": "https://github.com/pyasn1/pyasn1/security/advisories/GHSA-fm9c-5rcf-2q5p",
          "tags": [
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          "url": "https://github.com/pyasn1/pyasn1/security/advisories/GHSA-fm9c-5rcf-2q5p"
        },
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          "url": "https://github.com/pyasn1/pyasn1/releases/tag/v0.6.5"
        }
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      "source": {
        "advisory": "GHSA-fm9c-5rcf-2q5p",
        "discovery": "UNKNOWN"
      },
      "title": "pyasn1: Quadratic CPU use in schemaless BER/CER/DER container decoding"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-119194",
    "datePublished": "2026-10-29T19:38:14.056Z",
    "dateReserved": "2026-10-29T16:04:48.728Z",
    "dateUpdated": "2026-10-29T19:38:14.056Z",
    "state": "PUBLISHED"
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          }
        ],
        "cveTags": [],
        "descriptions": [
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            "value": "pyasn1 is a generic ASN.1 library for Python. From 0.3.3 until 0.6.5, schemaless container decoding stores every decoded component\u0027s TagSet in a growing set even though only one-versus-multiple tag types must be distinguished. Attacker-controlled BER, CER, or DER input contains many distinct long tag IDs whose TagSet hashes collide. Each later set insertion compares against an increasing number of earlier colliding tags in ConstructedPayloadDecoderBase._decodeComponentsSchemaless, producing quadratic CPU work while decoded values and order remain valid. Repeated inputs can exhaust decoder CPU and reduce service availability. This issue is fixed in version 0.6.5."
          }
        ],
        "id": "CVE-2026-119194",
        "lastModified": "2026-10-29T20:17:30.480",
        "metrics": {
          "cvssMetricV31": [
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                "attackComplexity": "LOW",
                "attackVector": "NETWORK",
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            "url": "https://github.com/pyasn1/pyasn1/commit/a36e3a3d067148d26197a6b7221fd0e2cde9cc86"
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        "vulnStatus": "Received",
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    }
  }
}



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