CVE-2026-49140
mediumpriority · track · 0EPSS 0.003 · 19 %ileEUEPSS · scored 2026-10-28
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.
cvss
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · low–medium · 1.3–5.3
ssvc
A stakeholder decision — act, attend, or track — from exploitation and impact.
weaknesses
The CWE weakness classes this flaw belongs to.
affected products (1)
Products and version ranges known to be affected.
also known as (3)
Other names and identifiers for this entity.
sources
Which sources assert this record, and when.
references (13)
External citations — patches, advisories, analysis.
- https://github.com/HKUDS/nanobot/commit/1d4000560dfff1acb83f5c5ca8ef3ab1f092bd14cnnvd
- https://github.com/HKUDS/nanobot/pull/4106cnnvd
- https://github.com/HKUDS/nanobot/releasesPatchcnnvd
- https://github.com/HKUDS/nanobot/releases/tag/v0.2.1cnnvd
- https://www.vulncheck.com/advisories/nanobot-denial-of-service-via-matrix-media-download-handlercnnvd
- https://github.com/HKUDS/nanobot/commit/1d4000560dfff1acb83f5c5ca8ef3ab1f092bd14enisa_euvd
- https://github.com/HKUDS/nanobot/pull/4106enisa_euvd
- https://github.com/HKUDS/nanobot/releases/tag/v0.2.1enisa_euvd
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