CVE-2026-49140 (GCVE-0-2026-49140)

Vulnerability from cvelistv5 – Published: 2026-06-01 19:54 – Updated: 2026-06-01 19:54 X_Open Source
VLAI
Title
Nanobot < 0.2.1 Denial of Service via Matrix Media Download Handler
Summary
Nanobot prior to version 0.2.1 contains a denial of service vulnerability in the Matrix channel media download handler that allows authenticated room members to exhaust process memory and bandwidth by sending media events with missing or invalid size metadata. Attackers can send multiple concurrent Matrix media events with omitted or invalid declared sizes to trigger simultaneous large media downloads that fully materialize response bodies before post-download rejection, consuming process resources until service degradation occurs.
Severity
5.3 (Medium)
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
4.3 (Medium)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
CWE
  • CWE-770 - Allocation of Resources Without Limits or Throttling
Assigner
References
Impacted products
Vendor Product Version
HKUDS nanobot Affected: 0 , < 0.2.1 (semver)
Create a notification for this product.
Date Public
2026-05-29 00:00
Credits
Chia Min Jun Lennon
Show details on NVD website
To clipboard 

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          "repo": "https://github.com/HKUDS/nanobot",
          "vendor": "HKUDS",
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              "status": "affected",
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      "credits": [
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        }
      ],
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            "Recovery": "NOT_DEFINED",
            "Safety": "NOT_DEFINED",
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            "attackRequirements": "NONE",
            "attackVector": "NETWORK",
            "baseScore": 5.3,
            "baseSeverity": "MEDIUM",
            "exploitMaturity": "NOT_DEFINED",
            "privilegesRequired": "LOW",
            "providerUrgency": "NOT_DEFINED",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "NONE",
            "valueDensity": "NOT_DEFINED",
            "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N",
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      "problemTypes": [
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          "descriptions": [
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              "description": "Allocation of Resources Without Limits or Throttling",
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              "type": "CWE"
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      "providerMetadata": {
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        "orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
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        },
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          "url": "https://github.com/HKUDS/nanobot/pull/4106"
        },
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          "url": "https://github.com/HKUDS/nanobot/commit/1d4000560dfff1acb83f5c5ca8ef3ab1f092bd14"
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        }
      ],
      "source": {
        "discovery": "UNKNOWN"
      },
      "tags": [
        "x_open-source"
      ],
      "title": "Nanobot \u003c 0.2.1 Denial of Service via Matrix Media Download Handler",
      "x_generator": {
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  },
  "cveMetadata": {
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    "assignerShortName": "VulnCheck",
    "cveId": "CVE-2026-49140",
    "datePublished": "2026-06-01T19:54:53.921Z",
    "dateReserved": "2026-05-27T17:40:12.739Z",
    "dateUpdated": "2026-06-01T19:54:53.921Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
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  }
}


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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.