CVE-2026-104874 (GCVE-0-2026-104874)

Vulnerability from cvelistv5 – Published: 2026-10-02 20:21 – Updated: 2026-10-02 20:21
VLAI
Title
Multidict: Reference leak in CIMultiDict/MultiDict items-view union and subtraction
Summary
Multidict is an implementation of a multidict data structure. From 6.7.0 until 6.9.1, the C extension's items-view reflected union operation, operand | d.items(), in multidict_itemsview_or2_impl and subtraction operation, d.items() - operand, in multidict_itemsview_sub1_impl fail to release new key-identity and value references returned for each operand element. Applications that perform these operations over attacker-influenced sequences can leak two strong references per element, and garbage collection cannot reclaim them, so repeated operations can cause unbounded process memory growth and denial of service. Forward union, intersection, non-tuple operand elements, and pure-Python builds are not affected by this reference leak. This issue is fixed in version 6.9.1.
Severity
5.3 (Medium)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
CWE
  • CWE-401 - Missing Release of Memory after Effective Lifetime
Assigner
References
Impacted products
Vendor Product Version CPE status
aio-libs multidict Affected: >= 6.7.0, < 6.9.1
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        }
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      "providerMetadata": {
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        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
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      "source": {
        "advisory": "GHSA-54p9-h82j-f925",
        "discovery": "UNKNOWN"
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      "title": "Multidict: Reference leak in CIMultiDict/MultiDict items-view union and subtraction"
    }
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  "cveMetadata": {
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    "cveId": "CVE-2026-104874",
    "datePublished": "2026-10-02T20:21:50.903Z",
    "dateReserved": "2026-10-02T14:59:11.775Z",
    "dateUpdated": "2026-10-02T20:21:50.903Z",
    "state": "PUBLISHED"
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  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
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          }
        ],
        "id": "CVE-2026-104874",
        "lastModified": "2026-10-02T21:16:54.993",
        "metrics": {
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            "url": "https://github.com/aio-libs/multidict/security/advisories/GHSA-54p9-h82j-f925"
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        "vulnStatus": "Received",
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    "redhat_vex": {
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      "current_release_date": "2026-10-02T20:49:28+00:00",
      "cve": "CVE-2026-104874",
      "id": "CVE-2026-104874",
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      "product_status:known_affected": "145",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "multidict: multidict: Denial of Service via memory leak in items-view operations",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-104874.json",
      "version": "3"
    }
  }
}



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