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CVE

CWE

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CVE-2026-49140

Published: Jun 1, 2026

Modified: Jun 2, 2026

PUBLISHED

CVSS v3.1

4.3

MEDIUM

Description

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.

Vendor	Product	Versions
HKUDS	nanobot	affected `0 - < 0.2.1`

Weaknesses (CWE)

CVSS v3.1 Details

CVSS v3.1 Vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

Low

References

https://github.com/HKUDS/nanobot/releases/tag/v0.2.1

release-notes

https://github.com/HKUDS/nanobot/pull/4106

issue-tracking

https://github.com/HKUDS/nanobot/commit/1d4000560dfff1acb83f5c5ca8ef3ab1f092bd14

patch

https://www.vulncheck.com/advisories/nanobot-denial-of-service-via-matrix-media-download-handler

third-party-advisory

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