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CVE-2026-49140

MEDIUMCVSS 5.3/10EPSS 0.27%

Last modified

CVE-2026-49140 is a medium-severity vulnerability rated 5.3/10 on the CVSS scale. 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.. EPSS estimates a 0.27% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1
4.3/10

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

CVSS 4.0
5.3/10

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS Probability
0.27%

18.3th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

References

Timeline

Published
Last Modified
Status
Deferred

Frequently Asked Questions

What is CVE-2026-49140?
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.
How severe is CVE-2026-49140?
CVE-2026-49140 has a CVSS score of 5.3/10 (MEDIUM severity). The EPSS model estimates a 0.27% probability of exploitation in the next 30 days.
How do I fix CVE-2026-49140?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-49140?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST