CVE-2026-49140
Nanobot < 0.2.1 Denial of Service via Matrix Media Download Handler
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.
INFO
Published Date :
June 1, 2026, 9:16 p.m.
Last Modified :
June 1, 2026, 9:16 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-49140
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | MEDIUM | 83251b91-4cc7-4094-a5c7-464a1b83ea10 | ||||
| CVSS 3.1 | MEDIUM | [email protected] | ||||
| CVSS 4.0 | MEDIUM | 83251b91-4cc7-4094-a5c7-464a1b83ea10 | ||||
| CVSS 4.0 | MEDIUM | [email protected] |
Solution
- Update Nanobot to version 0.2.1 or later.
- Validate media event size metadata.
- Monitor resource utilization closely.
- Implement rate limiting for media events.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-49140.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-49140 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-49140
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-49140 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-49140 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
New CVE Received by [email protected]
Jun. 01, 2026
Action Type Old Value New Value Added 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. Added CVSS V4.0 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 Added CVSS V3.1 AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L Added CWE CWE-770 Added Reference https://github.com/HKUDS/nanobot/commit/1d4000560dfff1acb83f5c5ca8ef3ab1f092bd14 Added Reference https://github.com/HKUDS/nanobot/pull/4106 Added Reference https://github.com/HKUDS/nanobot/releases/tag/v0.2.1 Added Reference https://www.vulncheck.com/advisories/nanobot-denial-of-service-via-matrix-media-download-handler