CVE-2026-15311
NousResearch hermes-agent Matrix Adapter matrix.py MatrixAdapter._markdown_to_html cross site scripting
Description
A vulnerability was identified in NousResearch hermes-agent up to 2026.5.29.2. Affected by this issue is the function MatrixAdapter._markdown_to_html of the file gateway/platforms/matrix.py of the component Matrix Adapter. Such manipulation leads to cross site scripting. The attack can be executed remotely. The exploit is publicly available and might be used. The pull request to fix this issue awaits acceptance.
INFO
Published Date :
July 10, 2026, 12:16 a.m.
Last Modified :
July 10, 2026, 12:16 a.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 2.0 | MEDIUM | [email protected] | ||||
| CVSS 3.1 | LOW | [email protected] | ||||
| CVSS 4.0 | LOW | [email protected] |
Solution
- Apply the pull request to fix the Matrix Adapter.
- Update NousResearch hermes-agent to the latest version.
- Validate the fix to ensure XSS is mitigated.
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-2026-15311.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-15311 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-2026-15311
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-2026-15311 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-15311 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.
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New CVE Received by [email protected]
Jul. 10, 2026
Action Type Old Value New Value Added Affected [{'cpes': ['cpe:2.3:a:nousresearch:hermes-agent:*:*:*:*:*:*:*:*'], 'vendor': 'NousResearch', 'modules': ['Matrix Adapter'], 'product': 'hermes-agent', 'versions': [{'status': 'affected', 'version': '2026.5.29.0'}, {'status': 'affected', 'version': '2026.5.29.1'}, {'status': 'affected', 'version': '2026.5.29.2'}]}] Added Description A vulnerability was identified in NousResearch hermes-agent up to 2026.5.29.2. Affected by this issue is the function MatrixAdapter._markdown_to_html of the file gateway/platforms/matrix.py of the component Matrix Adapter. Such manipulation leads to cross site scripting. The attack can be executed remotely. The exploit is publicly available and might be used. The pull request to fix this issue awaits acceptance. Added CVSS V4.0 AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:P/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:R/S:U/C:N/I:L/A:N Added CVSS V2 (AV:N/AC:L/Au:S/C:N/I:P/A:N) Added CWE CWE-79 Added CWE CWE-94 Added Reference https://github.com/NousResearch/hermes-agent/ Added Reference https://github.com/NousResearch/hermes-agent/issues/42667 Added Reference https://github.com/NousResearch/hermes-agent/pull/42759 Added Reference https://vuldb.com/cve/CVE-2026-15311 Added Reference https://vuldb.com/submit/852843 Added Reference https://vuldb.com/vuln/377247 Added Reference https://vuldb.com/vuln/377247/cti