| Component | Nanobot |
| Severity | medium (CVSS 4.3) |
| CVSS vector | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L |
| Published (NVD) | 2026-06-01 |
| Last modified | 2026-06-02 |
| Affected versions | < 0.2.1 read from the advisory text: NVD has not published CPE data yet |
| Fixed in | 0.2.1 |
| Weakness | CWE-770 |
| CISA KEV | not listed |
NVD 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.
What to do
- Upgrade Nanobot to
0.2.1or later. - Do not expose the component's API or UI to the internet without authentication in front of it.
Sources
- NVD: CVE-2026-49140
- https://github.com/HKUDS/nanobot/commit/1d4000560dfff1acb83f5c5ca8ef3ab1f092bd14
- https://github.com/HKUDS/nanobot/pull/4106
- https://github.com/HKUDS/nanobot/releases/tag/v0.2.1
- https://www.vulncheck.com/advisories/nanobot-denial-of-service-via-matrix-media-download-handler
Other Nanobot CVEs
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A vulnerability has been found in HKUDS nanobot up to 0.2.1. This affects the function _download_image_data_url of the file nanobot/provider...
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A security vulnerability has been detected in HKUDS nanobot up to 0.2.1. Impacted is the function ExecTool._guard_command/ExecTool._spawn of...
A flaw has been found in HKUDS nanobot up to 0.2.1. The impacted element is the function ExecTool._prepare_command of the file nanobot/agent...