CVE-2026-49140
Nanobot < 0.2.1 Denial of Service via Matrix Media Download Handler
- State
- Published
- Severity
- 5.3 Medium
- Published
- Jun 1, 2026
- Updated
- Jul 28, 2026
- Reserved
- May 27, 2026
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 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 | VulnCheck |
| 3.1 | 4.3 Medium | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L | VulnCheck |
Weaknesses
- CWE-770 Allocation of Resources Without Limits or Throttling
Affected Products
| Product | Versions |
|---|---|
nanobotHKUDS |
|
References
- https://github.com/HKUDS/nanobot/releases/tag/v0.2.1release-notes
- https://github.com/HKUDS/nanobot/pull/4106issue-tracking
- https://github.com/HKUDS/nanobot/commit/1d4000560dfff1acb83f5c5ca8ef3ab1f092bd14patch
- https://www.vulncheck.com/advisories/nanobot-denial-of-service-via-matrix-media-download-handlerthird-party-advisory
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