CVE-2026-119194

Full vulnerability record from the local CVENow database.

Description

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

HIGH

CVSS score

7.5 (v3.1)

Vulnerability status

Received

Source identifier

[email protected]

Published

2026-10-29 20:17:30.480000

Last modified

2026-10-29 20:17:30.480000

View original CVE JSON

{
  "id": "CVE-2026-119194",
  "sourceIdentifier": "[email protected]",
  "published": "2026-10-29T20:17:30.480",
  "lastModified": "2026-10-29T20:17:30.480",
  "vulnStatus": "Received",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "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'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."
    }
  ],
  "affected": [
    {
      "source": "[email protected]",
      "affectedData": [
        {
          "vendor": "pyasn1",
          "product": "pyasn1",
          "versions": [
            {
              "version": ">= 0.3.3, < 0.6.5",
              "status": "affected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {
    "cvssMetricV31": [
      {
        "source": "[email protected]",
        "type": "Secondary",
        "cvssData": {
          "version": "3.1",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
          "baseScore": 7.5,
          "baseSeverity": "HIGH",
          "attackVector": "NETWORK",
          "attackComplexity": "LOW",
          "privilegesRequired": "NONE",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "availabilityImpact": "HIGH"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 3.6
      }
    ]
  },
  "weaknesses": [
    {
      "source": "[email protected]",
      "type": "Primary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-407"
        }
      ]
    }
  ],
  "references": [
    {
      "url": "https://github.com/pyasn1/pyasn1/commit/a36e3a3d067148d26197a6b7221fd0e2cde9cc86",
      "source": "[email protected]"
    },
    {
      "url": "https://github.com/pyasn1/pyasn1/pull/132",
      "source": "[email protected]"
    },
    {
      "url": "https://github.com/pyasn1/pyasn1/releases/tag/v0.6.5",
      "source": "[email protected]"
    },
    {
      "url": "https://github.com/pyasn1/pyasn1/security/advisories/GHSA-fm9c-5rcf-2q5p",
      "source": "[email protected]"
    }
  ]
}