CVSS 4.0
5.3 mediumCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:NCVE-2026-49140
Medium (5.3). EPSS 0.3% chance of exploitation in the next 30 days.
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
CVSS 3.1
4.3 mediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L- EPSS
- 0.3% chance of exploitation in the next 30 days; higher than 19% of CVEs (scores of 2026-10-31)
- CWE
- CWE-770
- Published
- Modified
- Record from
- the NVD, synced
References
- 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
- https://github.com/HKUDS/nanobot/pull/4106